DOT Projects Vol II Guidance ICI

Guidance for Assessing Indirect and
Cumulative Impacts of Transportation
Projects in North Carolina
Volume II: Practitioner's Handbook
Prepared For:
State of North Carolina
Department of Transportation/Department of
Environment and Natural Resources
Raleigh, North Carolina
Under Project No. 81777722
Prepared By:
The Louis Berger Group, Inc.
Cary, North Carolina
d.,aS?AtEa'
Issued November 2001
ACKNOWLEDGEMENT
This document reflects the proceedings and efforts of a Joint-agency Task Force on
Indirect and Cumulative Effects of the North Carolina Department of Transportation and
the North Carolina Department of Environment and Natural Resources. Participants in
the effort included the following individuals:
Name Affiliation
Janet D'Ignazio Department of Transportation
Gail Grimes Department of Transportation
Robin Smith Department of Environment and Natural Resources
Dan McLawhorn Department of Environment and Natural Resources
Melba McGee Department of Environment and Natural Resources
William Funk Department of Environment and Natural Resources
Chrys Baggett Department of Administration
Fred Lamar Attorney General's Office - Transportation
Lisa Glover Attorney General's Office - Transportation
Katherine Batey Federal Highway Administration
Mike Dawson Federal Highway Administration
Henry Lancaster Association of County Commissioners
James Blackburn Association of Municipalities
Byron O'Quinn Arcadis, Geraghty & Miller (Advisor)
The Louis Berger Group, Inc. served as consultant to the Task Force.
,. ,.. ,
_, . ., _
TABLE OF CONTENTS
Executive Summary ......................................................... I-1
Section I: How This Handbook Is Organized ................................. I-1
Section II: Pre-Screening Projects for Applying
Indirect/Cumulative Impact Assessment ........................... II-1
Section III: Developing the Scope of the
Indirect/Cumulative Impact Assessment .......................... III-1
Chapter 1: Step 1- Defining the Study Area Boundaries .......................... III-3
Overview ........................................................... III-3
Boundary-Setting Techniques ........................................... III-4
Political/Geogrpahic Boundaries .................................. III-4
Commuteshed ................................................. III-5
Growth Boundaries/Service Area Limits ............................ III-6
Watershed/Habitat .............................................. III-6
Interview/Public Involvement ..................................... III-6
Timeframe Considerations .............................................. III-7
Combining Study Area Tools ........................................... III-7
Work Product of Step 1 ................................................ III-8
Chapter 2: Step 2- Identify the Study Area's Directions and Goals ................ III-11
Overview .......................................................... III-11
Considerations ...................................................... III-12
Timing ...................................................... III-12
Data Collection ............................................... III-12
Methods ........................................................... III-16
Step 2A - Data Collection ....................................... III-16
Step 2B - Public Involvement .................................... III-23
Work Product for Step 2 .............................................. III-25
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Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Chapter 3: Step 3 - Inventory Notable Features ................................ III-27
Overview .......................................................... III-27
Considerations ...................................................... III-27
Methods ........................................................... III-29
Step 3A - Assemble Inventory of Ecosystem Conditions ............... III-29
Step 3B - Assemble Inventory of Socioeconomic Conditions ............ III-29
Step 3C - Assemble Inventory of Notable Features .................... III-31
Application to Practice ................................................ III-31
Transportation Systems Planning Context ........................... III-31
Project Evaluation Context ...................................... III-31
Work Product of Step 3 ............................................... III-32
Chapter 4: Step 4 - Identify Impact-Causing Activities .......................... III-41
Overview .......................................................... III-41
Considerations ..................................................... III-42
Methods ........................................................... III-43
Application to Practice ............................................... III-47
Transportation Systems Planning Context ........................... III-47
Project Evaluation Context ...................................... III-47
Work Product of Step 4 .............................................. III-47
Chapter 5: Step 5 - Identify Potential Indirect/Cumulative Impacts for Analysis ...... III-49
Overview .......................................................... III-49
Considerations ..................................................... III-49
Encroachment-Alteration Effects .................................. III-50
Ecological Effects ....................................... III-50
Socioeconomic Effects .................................... III-54
Induced Growth Effects ......................................... III-56
Projects Planned to Serve Specific Land Development ........... III-57
Projects Likely to Stimulate Complementary Land Development ... III-61
Projects Likely to Influence Intraregional Location Decisions ..... III-61
Effects Related to Induced Growth ................................ III-63
Methods ........................................................... III-69
Application to Practice ................................................ III-71
Transportation Systems Planning Context ........................... III-71
Project Evaluation Context ...................................... III-72
Work Product of Step 5 ............................................... III-72
Resources and Supplemental Readings ................................... III-73
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Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Section IV: Analysis of Indirect/Cumulative Effects ......................... IV-1
Chapter 6: Step 6 - Analyze Indirect/Cumulative Effects ......................... IV-3
Overview ........................................................... IV-3
Considerations ....................................................... IV-3
Methods for Analysis .................................................. IV-3
Qualitative Forecast Tools ........................................ IV-3
Literature Review/Comparative Case Analysis .................. IV-5
Scenario Writing .........................................IV-6
Delphi Technique/Expert Panel Survey/Public Involvement ....... IV-6
Quantitative Forecast Tools ....................................... IV-9
Trend Extrapolation ....................................... IV-9
Build-Out/Carrying-Capacity Analysis ....................... IV-13
Regression Analysis/Econometric Forecasting Techniques ....... IV-15
Simple Gravity Model .................................... IV-16
Economic and Fiscal Impact Modeling/Cost-Benefit Analysis ..... IV-18
Integrated Land Use and Transportation Models ................ IV-21
Application of Analysis Techniques ............................... IV-23
Analyzing Induced Development .................................. IV-25
Specific Development Proposals ........................... IV-25
Complementary Development ............................. IV-25
Intra-Regional Development Shifts ......................... IV-26
Transportation Systems Planning ................................. IV-26
Project Evaluation ............................................. IV-30
Analysis of Encroachment Alteration Effects .............................. IV-32
Work Product of Step 6 ............................................... IV-35
Resources and Supplementary Readings ...................... IV-37
Chapter 7: Step 7 - Evaluate Analysis Results ................................ IV-39
Overview ..........................................................IV-39
Considerations ......................................................IV-40
Basic Technique for Analysis Evaluation ................................. IV-40
Detailed Techniques for Analysis Evaluation .............................. IV-41
Resources and Supplementary Readings .................................. IV-43
Section V: Assessing the Consequences ..................................... V-1
Chapter 8: Step 8 - Assess the Consequences and Develop Appropriate
Mitigation and Enhancement Strategies ............................. V-3
Overview ........................................................... V-3
Considerations ....................................................... V-3
Providing the Basis for Informed Decision Making .................... V-4
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Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Determining When a Potential Impact Should Be Considered Unacceptable . V-4
Mitigation for Impacts to Notable Features ........................... V-5
Determining the Practicability of Mitigation .......................... V-5
Responsibility for Mitigation and the Role of the Sponsoring Agency ...... V-5
Methods ............................................................ V-7
Mitigation Techniques for Encroachment-Alteration Effects ............. V-9
Mitigation Techniques for Induced Growth ........................... V-9
Techniques Available to the NCDOT ......................... V-9
Techniques Available to Other Entities ...................... V-10
Mitigation Techniques for Effects Related to Induced Growth ........... V-12
Techniques Available to the NCDOT ........................ V-12
Techniques Available to Other Entities ...................... V-12
Techniques for the Systems Planning Stage ......................... V-14
Work Product for Step 8 .............................................. V-15
Resources and Supplemental Readings ................................... V-16
Appendix A: Sample Survey Instrument ............................................ A-1
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
LIST OF FIGURES
Figure II-1: Characterization of New Highway Construction ........................ U-2
Figure II-2: Minimum Project-Level Pre-screening Thresholds for
Indirect/Cumulative Effects Linked to Transportation System
Access Changes ................................................. II-5
Figure III-1: Combining Study Area Techniques ................................. III-9
Figure III-2: CEQ Goals for Ecosystem (Biodiversity) Management ................ III-15
Figure III-3: Description of Data Sources for Identification of Goals and Trends ....... III-18
Figure III-4: Organization and Tabulation of Goals Chart ......................... III-21
Figure III-5: Study Area Directions and Goals Checklist .......................... III-22
Figure III-6: Ecosystem Conditions Inventory .................................. III-33
Figure III-7: Socioeconomic Conditions Inventory .............................. III-34
Figure III-8: Notable Features Checklist ...................................... III-35
Figure III-9: Notable Features Addressed by Federal and NC Statutes ............... III-36
Figure III-10: Other Activities (Existing and Proposed) That May Cumulatively
Affect Notable Features ......................................... III-44
Figure III-11: Project Impact-causing Activities Checklist ......................... III-46
Figure III-12: Components of Biological Diversity ............................... III-52
Figure III-13: Some Possible Effects on Ecosystems from Transportation Projects ...... III-53
Figure III-14: Conceptual Approach to Effect Identification ........................ III-55
Figure III-15: Highway Investment Impact on Typical Progress of Urbanization ........ III-58
Figure III-16: Transportation Access-Land Use Change Linkage .................... III-59
Figure III-17: Simplified Model of Various Factors Influencing
Development Location Decisions ................................. III-60
Figure III-18: Effects of Land Development and Indicators for Estimation ............. III-65
Figure III-19: Possible Effects of Land Development on Socioeconomic Variables ...... III-68
Figure III-20: Examples of Indirect Effects ..................................... III-74
Figure III-21: Examples of Cumulative Effects .................................. III-77
Figure III-22: Decision Tree for Scoping Potentially Significant Effects .............. III-78
Figure 7-11: Evaluation Matrix for Effects Requiring Detailed Analysis ............. III-80
Figure IV-1: Delphi Study Process ............................................ IV-8
Figure IV-2: Examples of Trend Extrapolation ................................. IV-11
Figure IV-3: Typical Values for Land Consumption by Land Use Type .............. IV-14
Figure IV-4: Factors to Consider When Matching Methodologies and Project Types .... IV-24
Figure IV-5: Criteria for Development Suitability at Rural Interchanges .............. IV-27
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Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Figure IV-6: Summary of Direct, Indirect, and Cumulative Effects .................. IV-36
Figure V-1: Indirect Effects Evaluation Framework and Process for Assessing Effect
Consequences and Developing Mitigation/Enhancement Strategies ........ V-8
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Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
EXECUTIVE SUMMARY
The North Carolina Department of Transportation (NCDOT), in consultation with the North
Carolina Department of Environment and Natural Resources (NCDENR), undertook to develop a
guidance document, or policy, for evaluating the indirect and cumulative effects of transportation
projects in January 1999. The assessment of indirect and cumulative effects is identified as a
requirement under the National Environmental Policy Act of 1969, as amended (NEPA), the
North Carolina Environmental Policy Act (SEPA), and under the Council on Environmental
Quality (CEQ) regulations implementing NEPA. However, there are limited standardized and
comprehensive rules, legislation, procedures or guidance available for implementing these
requirements. Compounding this shortcoming is the apparent confusion regarding basic
definitions and terms, such as the extent of corporal and temporal boundaries in determining these
effects. These problems have hindered the assessment of indirect and cumulative effects in
environmental impact statements throughout the country.
The purpose of this guidance is to provide NCDOT NEPA/SEPA practitioners with a tool to help
in the identification, analysis and assessment of indirect and cumulative effects of transportation
projects as part of the NEPA/SEPA assessment process. This guidance is also intended to help
federal and state environmental regulatory and resource agencies, such as NCDENR, to
understand the assessment of indirect and cumulative effects and to provide a "standard" for
reviewing NEPA/SEPA assessment documents. Specifically, this guidance is intended to meet
the following objectives:
? Describe the terminology related specifically to indirect and cumulative effects assessment as
defined by regulations and clarified by the courts.
? Apply the existing case law regarding indirect and cumulative effects assessment to
interpretations of terms and applicable practices under NEPA/SEPA.
? Provide direction on project scoping issues and their implications for addressing indirect and
cumulative effects.
? Provide direction on identification and evaluation of project-induced growth effects.
? Describe various methodologies and techniques, which may be considered when undertaking
indirect and cumulative effects assessment.
? Describe a framework for incorporating in indirect and cumulative effects in NEPA/SEPA
documents, e.g., environmental assessments or environmental impact statements, as well as in
the planning and other activities, which precede the documents.
This volume, Volume II: Practitioner's Handbook, describes the "how-to" methods of
indirect/cumulative impact assessment. Volume I: Guidance Policy Report, comprises the
technical, memoranda prepared for the agencies' review in developing the guidance.
Executive Summary Page ES-1
Guidance on Indirect and Cumulative Impact Assessment Volume M. Practitioner's Handbook
SECTION I
HOW THIS HANDBOOK IS ORGANIZED
This Handbook presents a Framework and supporting methods suggested for indirect/cumulative
impact assessment. The steps of the Framework generally conform with conventional impact
assessment approaches. However, as with many assessments, there are a variety of tools and
techniques that may be employed to suit the project-specific circumstances. Accordingly,
checklists and flowcharts have been provided at each step to guide the organization and
assessment of data. Use of these tools is recommended but not required.
Application of the Framework is not appropriate or necessary for all transportation projects.
Section II of the Handbook describes thresholds to sort projects into those for which the
indirect/cumulative impact assessment is normally warranted and those for which it is not.
Practitioners are advised, however, that even though an indirect/cumulative impact assessment
may not appear to be warranted for a particular project based on the thresholds, project-specific
circumstances may dictate otherwise. Therefore, it is suggested that involved parties be
consulted, as appropriate, before determining that an assessment is not necessary, and that the
reasons supporting that conclusion be fully documented in the environmental documentation for
the project.
The Framework consists of eight steps organized into three main groupings:
? Section III - Developing the Scope of the Indirect/Cumulative Impact Assessment
? Section N - Analysis of Indirect/Cumulative Effects
? Section V - Assessing the Consequences
Indirect/cumulative impact assessment typically cuts across many disciplines. It is
recommended that a multidisciplinary approach be used when applying the Framework.
Section 1: Handbook Organization Page 1-1
1 ... .. .
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
SECTION II
PRE-SCREENING PROJECTS FOR APPLYING
INDIRECT/CUMULATIVE IMPACT ASSESSMENT
Not all proposed transportation projects will cause measurable indirect effects or contribute to
measurable cumulative effects. In light of effective utilization of agency resources, it is
appropriate that transportation projects be subject to a level of analysis that is commensurate
with the potential magnitude and importance of potential indirect/cumulative effects attributable
to the project.
Can proposed transportation projects be pre-screened (or sorted) into those which should be
evaluated through application of the indirect/cumulative impact assessment framework versus
those for which application of the framework is not normally warranted? The answer to this
question depends in large part on the type of indirect/cumulative impact in question.
It is difficult to apply a general pre-screening threshold for those indirect/cumulative effects on
resources that are solely linked to the project "foot print" (e.g., limits of disturbance) rather than
linked to transportation system access alterations and associated changes in land use. Whether
or not to apply the indirect/cumulative impact assessment framework in such cases will often
depend on whether there is potential for effects on resources subject to Federal or North Carolina
statutes. If there is no such potential, then evaluation of the project under the indirect/cumulative
impact assessment framework will normally not be warranted. If there is such potential, then the
indirect/cumulative effects should generally be considered in conjunction with the direct effects
under the pertinent resource heading(s) in the environmental document and, if applicable, as part
of the permit application(s).
Generally, for a transportation project to cause changes in accessibility that lead to land use
changes and changes in travel patterns (and concomitant impacts on resources), the project needs
to be located on a particular type of transportation facility. It is generally accepted, e.g., for
purposes of transportation conformity, that such "regionally significant" projects are normally
located on facilities classified as principal arterials or above (and equivalent transit facilities).
These projects can be identified by completing the project data sheet Figure H-1.
Transportation improvements on such facilities that can lead to changes in land use are listed on
Figure H-2. Under most circumstances, evaluation of the types of indirect/cumulative effects
linked to alteration in transportation system access and related changes will not be warranted
when the project is on a facility that does not serve the functions of, or is of lesser magnitude
than those listed in Figure H-2.
Section 11: Pre-Screening of Projects Page 11-1
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
FIGURE II-1
CHARACTERIZATION OF NEW HIGHWAY CONSTRUCTION
1. Type of new construction:
a. Bypass: yes no
b. Connector Road: yes no
c. Roadway Relocation: yes no
d. New Highway Construction: yes no
e. New Interchange Construction: yes no
f. Others: yes no describe:
Please answer questions 2 and 3 relating to current conditions on the Primary existing route. If a
model is used, please provide node numbers.
2. Road Section Description
a. Name (SR Route):
b. From:
c. To:
d. Segment Length:
e. Function Class (Check one):
Rural Interstate
_ Major Collector
_ Urban Interstate
Minor Art.
Node #
Node #
Other Princ. Art.
_ Minor Collector
- Other Freeway
- Major Collector
Minor Art.
_ Local
_ Other Princ. Art.
Local
f. Area Type (check one) - Rural - Small Urban _ Urban
3. Traffic Data:
a. Annual Average Daily Traffic (AADT) Volume: veh/day
The above traffic count is (check one): One-way Two-way
b. Average Daily Weekday Traffic (ADWT) in July: veh/day
c. The above traffic count is (check one): One-way Two-way
Section ll: Pre-Screening of Projects Page 11-2
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Please answer questions 4 and 5 concerning the new location. If a model is used, please provide
node numbers.
4. New Road Description:
a. Name (SR Route):
b. From: Node #
c. To: Node #
d. Segment Length:
e. Function Class (Check one):
_ Rural Interstate
_ Major Collector
Urban Interstate
Minor Art.
_ Other Princ. Art. _ Minor Art.
_ Minor Collector _ Local
-Other Freeway - Other Princ. Art.
_ Major Collector - Local
f. Area Type (check one) - Rural - Small Urban _ Urban
5. Traffic Forecast (not needed for model):
a. New alignment volume: Estimated average daily traffic: veh/day
The above traffic estimate is (check one): One-way Two-way
b. Estimated Peak Hour Diversion from Parallel Facilities:
i. From Freeways:
From Street:
To Street:
From Street:
To Street:
From Street:
To Street:
Volume (vph)
Volume (vph)
Volume (vph)
Section 11: Pre-Screening of Projects Page II-3
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
H. From Arterials:
From Street:
To Street:
From Street:
To Street:
From Street:
To Street:
iii. From Locals:
From Street:
To Street:
From Street:
To Street:
From Street:
To Street:
Volume (vph)
Volume (vph)
Volume (vph)
Volume (vph)
Volume (vph)
Volume (vph)
Section 11: Pre-Screening of Projects Page II-4
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
FIGURE II-2
MINIMUM PROJECT-LEVEL PRE-SCREENING THRESHOLDS FOR
INDIRECT/CUMULATIVE EFFECTS LINKED TO TRANSPORTATION SYSTEM
ACCESS CHANGES
1) Highway/Roadway
a) New construction or new location of Principal Arterial or above, one mile or
longer;
b) Widening of Principal Arterial or above to provide additional through-traffic
lanes, one mile or longer (urban) or 2.5 miles or longer (rural); and
c) Additional grade-separated ramps or new interchanges on Principal Arterials or
above.
2) Transit/Rail
d) New passenger rail service and extensions of existing service, 5 miles or longer;
e) Purchase of additional (not replacement) rolling stock to support increased
frequency and higher ridership;
f) Rail connections to provide new regional service; and
g) New rail stations and new or expanded rail park-and-ride facilities resulting in
100 new parking spaces.
Section II: Pre-Screening of Projects Page II-5
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
SECTION III
DEVELOPING THE SCOPE OF THE
INDIRECT/CUMULATIVE IMPACT ASSESSMENT
Scope development is the key to proper and timely identification and analysis of
indirect/cumulative effects. Whether accomplished through formal scoping at the onset of EIS
preparation or otherwise, scope development provides the best opportunity to identify potentially
significant issues, set appropriate boundaries for the analysis, and identify relevant past, present
and future actions. Scoping also allows for the setting of the environmental baseline to which all
effects are compared.
Under the federal Council on Environmental Quality (CEQ) regulations (40 CFR 1500-1508),
specific details regarding scoping are provided at § 1501.7. As part of this scoping the lead
agency should:
"determine the scope and significant issues to be analyzed in depth in the Environmental
Impact Statement." (§ 1501.7(a)(2));
"identify and eliminate from detailed study the issues which are not significant or which
have been covered by prior environmental review" (§ 1506.3); and
? narrow "the discussions of these issues in the statement to a brief presentation of why
they will not have a significant effect on the human environment or providing a reference
to their coverage elsewhere." (§ 1501.7(a)(3)). These issues include those that have
indirect and cumulative effects as well as direct effects.
The scope of the indirect/cumulative impact assessment should generally identify social, cultural
and natural (physical and ecological) resource issues that effect the human environment; and
identify potentially significant issues and effects for further analysis. Full identification and
consideration of these issues involves working through the following steps of the framework as
part of scope development.
? Step 1 - Define the Study Area Boundaries;
? Step 2 - Identify the Study Area's Direction and Goals;
? Step 3 - Inventory Notable Features;
? Step 4 - Identify Impact Causing Activities of the Proposed Action and Alternatives; and
Section III: Developing the Scope Page III-]
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Step 5 - Identify Potential Indirect/Cumulative Effects For Analysis.
These steps and the methodologies appropriate for carrying them out are described in detail in
Chapters I through 5 that follow.
Section 111: Developing the Scope Page III-2
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Chapter 1
Step 1- Defining the Study Area Boundaries
Overview
When estimating the direct effects of a proposed project, study areas are often delineated using a
set distance, e.g., from the centerline or right-of-way limits. Since indirect/cumulative effects
can occur at a distance in time or space from the proposed project, broader limits, often not a
uniform distance from the proposed project, must be set. Techniques for determining study
areas fall into several general categories:
? political/geographic;
? commuteshed;
? growth boundary/service area;
? watershed/habitat; and
? interview/public involvement.
In most analyses, these catagories are combined to create a study area that will encompass all
potential indirect and cumulative effects relevant to an action. It can also be expected that study
area boundaries may be adjusted in the course of a study as resource areas and potential effects
are identified with more specificity.
This chapter will:
? describe the basic techniques for setting study area boundaries;
? discuss the considerations for setting the timeframe for evaluation of indirect/cumulative
effects; and
? outline how study area techniques may be combined to ensure a comprehensive
evaluation.
Section III: Developing the Scope Page 111-3
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Boundary -Setting Techniques
There are several techniques to choose from when setting the physical boundaries of the study
area. The techniques and considerations for their implementation are detailed below. In general,
study areas should encompass the project or plan alternatives in their entirety and also include
the surrounding physical, social, and natural resources that could be expected to be impacted by
the project or plan.
Political/Geographic Boundaries
Study area boundaries based on the limits of political jurisdictions or geographic features often
work to facilitate analysis for the following reasons:
? many existing data sources such as demographics, growth projections, comprehensive
plans, and resource inventories are delineated by political jurisdictions;
? stakeholders and the public can easily understand familiar political or geographic
boundaries; and
? land use regulations and other measures to control growth are enacted on the county or
municipal level.
Examples of political or geographic boundaries include:
? counties
? minor civil divisions (municipalities)
? tribal lands
? planning districts
? special improvement districts and enterprise zones
? census tracts or block groups
? traffic analysis zones or aggregations of zones
? rivers, water bodies, mountain ranges
While using political or geographic boundaries can make the task of data gathering and the
presentation of findings easier, care should be taken to avoid the following errors:
Section III: Developing the Scope Page III-4
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
? Undersized study area - Dividing lines between political jurisdictions are often arbitrary
and do not reflect present or future trends in development. Similarly, habitat areas or
areas of social cohesion may cross these dividing lines. For this reason, this method may
be most appropriate after an examination of community characteristics, commute
patterns, growth trends, or habitat locations using the methods below. The study area can
then be increased in size to match the boundaries of a political jurisdiction or group of
jurisdictions that encompass important features. The choice of a study area along
political or geographic boundaries should always be done so as to increase the size of the
study area.
? Oversized study area - While an oversized study area is preferable to a smaller one, a
larger study area will require a greater commitment to data gathering and analysis. A
larger study area also may increase the threshold for consideration of when
environmental features can be considered notable. This may cause impacts on smaller
community or habitat features to be overlooked.
Commuteshed
Effects related to project-induced development are dependent upon changes in accessibility.
Projects that have the potential to substantially alter travel times to major regional demand
generators may make an area more attractive to growth and development. To fully account for
this effect, a study area should be sized to coincide with a set commuting range or travel time to
a major destination. Destinations should be of a size and type sufficient to affect the locational
choices of future residents or employers and include city centers, or major regional employment
centers such as office or industrial parks, or suburban commercial centers.
Commuteshed boundaries can be determined through several techniques:
? Census data can be used to set the commuting time threshold. For example, most
commutes in many parts of the nation are 20 to 30 minutes in duration. The journey-to-
work questions on the Decennial Census provide information on the range of commute
times in a county, municipality or census tract by mode of transportation. The Census
Transportation Planning package available from the Bureau of Transportation Statistics
(U.S. DOT) provides characteristics of workers, of persons, workers, and housing units at
the traffic analysis zone (TAZ) level. For projects of regional significance or
transportation systems planning, journey-to-work county flow files available at the
Census internet site show county of origin by place of work or county of employment by
place of residence.
? Origin and destination surveys conducted by a regional planning agency, or for study of
the need for proposed project or other projects in the study area can be used to delineate a
study area by grouping together the most frequent pairings of origins and destinations.
Section 111: Developing the Scope Page 111-5
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Travel demand model output can also be used to delineate a study area based on flows
between TAZs.
When using the commute threshold technique, the study area should, whenever possible, take the
travel time savings of the project alternatives into account. This can be accomplished by setting
the study area to coincide with the area accessible under the alternative that provides the greatest
time savings. Similarly, output from a travel demand model of the alternative with the most time
savings would be appropriate. Origin and destination surveys are not dynamic and, therefore,
may not be practical in situations where there is a great difference in travel time between the no-
build and build scenarios.
Growth Boundaries/Service Area Limits
Jurisdictions with growth management policies, areas planned for development, or areas
expected to see growth in population or employment may already be delineated in long-range
infrastructure (sewer/water districts) or growth management plans. In some cases development
beyond this area, or the extension of infrastructure to serve it, is limited or restricted. In these
circumstances it may be appropriate to confine consideration of indirect/cumulative effects to a
study area coincident with accepted growth boundaries. When doing so, efforts should be made
to evaluate the effectiveness or strength of the growth regulations to confirm that development
beyond the proscribed area is indeed unlikely. It should also be confirmed that no encroachment
alteration effects arising from the project could occur outside this growth boundary study area.
Watershed/Habitat
Encroachment-alteration effects arising from a project or project-induced growth may have
immediate effects on a watershed or habitat that give rise to broader ecosystem, water quality, or
water quantity issues. To anticipate the full range of effects, it may be appropriate to size the
study area to match the extent of potentially impacted watersheds or habitat features. This can
be accomplished through a baseline screening of notable features of the natural environment
(Chapter 3).
Interview/Public Involvement
Stakeholder interviews, expert panel techniques, task forces, or other public involvement efforts
can be utilized to define a study area, or approve or refine a study area created with any of the
techniques described here. The general approach is to query experts or stakeholders about the
geographic extent of potential effects or test the validity of findings derived from another
technique.
Section III: Developing the Scope Page 111-6
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Timeframe Considerations
Since indirect/cumulative effects can be distant from the project in both time and space, setting a
time horizon for the analysis is another goal of scoping. The time frame should be short enough
in duration to anticipate reasonably foreseeable events, but should be long enough in duration to
capture the development and relocation effects that may only transpire over the course of several
business cycles. Most indirect/cumulative effects study set a time horizon equal to the design
life of a project, usually twenty to twenty-five years. This is also the time horizon used in most
MPO and county level planning forecasts.
Combining Study Area Tools
Because each of the study area techniques described above are related to particular types of
physical, natural, or social resources, it is often necessary to combine the techniques to produce a
study area suitable for consideration of the full range of potential indirect/cumulative effects. An
illustration of boundary technique combination appears in Figure III-1 and an example is as
follows:
? A commuteshed or growth boundary technique could be utilized to define the area for
consideration of induced growth effects.
? A habitat or watershed approach could be added to ensure consideration of
encroachment-alteration effects or environmental effects related to induced growth.
? To facilitate data gathering, the size of this combined study area may be increased to
encompass an entire political or data unit or groupings of those units, for example
counties, municipalities, or groupings of TAZs.
? The delineated study area and the methods used could then be presented to stakeholders
and other interested parties to seek their concurrence.
Recognizing that some techniques will not be appropriate in every situation, the analyst should
choose a technique or set of techniques that best fit the resources, potential effects, and data
available in a particular area. Choice of a study area and the techniques used to establish it
should be well documented, and it should be recognized that it may be necessary to change study
area boundaries if new information regarding resources or potential effects is revealed during the
remainder of the scoping process.
Section III: Developing the Scope Page 111-7
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Work Product of Step 1
The work product of the study area delineation effort should be a map delineating the study area
boundaries accompanied by brief technical memorandum describing the methods employed in
the determination.
Section III: Developing the Scope Page 111-8
Figure III-l: Combining Study Area Techniques
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Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Chapter 2
Step 2 - Identify the Study Area's Directions and Goals
Overview
After delineation of the study area is complete, it becomes important to begin to gather a wide
range of data describing baseline conditions in study area. This second step in the
indirect/cumulative effects assessment framework will focus on assembling information
regarding general trends and goals within the study area. The trends and goals in question are
independent of the proposed transportation project and typically concern social, health,
economic, ecological, and/or growth-related issues.
Empirical evidence indicates that transportation investments result in major land use changes
only in the presence of other factors. These factors include:
? supportive local land use policies;
? local development incentives;
? availability of developable land; and
? a good investment climate.
An understanding, therefore, of community goals, combined with a thorough knowledge of
demographic, economic, social, and ecological trends is essential in understanding the dynamic
of project induced growth. Later in the process, it will also be important to compare study area
goals with potential impacts. Conflict between impacts and goals is a key determinant of impact
significance and an indicator of effects that merit further analysis. Knowledge of goals and
trends will also facilitate an evaluation of project alternatives and the formulation of strategies to
meet all community and regional goals.
There are a variety of considerations related to identification of study area trends and goals.
This chapter will provide practitioners with an overview of these considerations and will:
? outline the types of goals and trends relevant to this step;
? highlight potential sources of information;
? describe techniques for data gathering and public involvement; and
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
? provide checklists useful for applying this step in practice.
Considerations
Timing
Ideally, this step should be timed to coincide with the process of problem identification and
needs assessment (deficiencies analysis), which is often the first step in the transportation
planning and development process. Conducting this step during the earliest part of the planning
process for transportation systems or projects will help to ensure that the social, economic, and
environmental goals of communities in the study areas will be evaluated in tandem with their
transportation needs in formulating proposals for transportation projects. It will also facilitate a
streamlined NEPA/SEPA process, promote the minimization of conflict between project effects
and study area goals, and work to reduce the need for mitigation and enhancement efforts after
the project is designed.
Because trends and goals are subject to change over time, and the length of time between the
planning process and NEPA/SEPA evaluation can be lengthy, it will be important to reevaluate
the currency of any data throughout the NEPA/SEPA process.
Analysts beginning the process of indirect/cumulative effects analysis after the project is
designed should make every effort to utilize information developed previously to assess project
purpose and need. Evaluations conducted for statewide planning purposes or transportation
plans developed by MPOs may also be useful.
Social, economic, and environmental goals expressed through formal plans reflect a current
vision of the future. Because of their inherent rippling effect over space and time, one way to
measure a transportation system's or project's indirect/cumulative effects is to envision the
future both with and without the system or project improvements. Consideration of various goals
early in the planning process can help focus the effort toward balancing transportation and other
needs, and also toward understanding potential indirect and cumulative effects.
Data Collection
Goals are typically spelled out in plans or policies. The content of available plans is typically
examined during the transportation project development process. For example, such plans can
provide future population and employment growth and land development information for the
study area. Further, the NEPA regulations (40 CFR 1508 and 23 CFR 771) require an evaluation
of project consistency with local plans. The literature indicates that better understanding of the
interrelationships between an area's transportation and other goals early in the process can lead
to better anticipation of a proposed transportation project's indirect/cumulative effects issues,
Section III: Developing the Scope Page III-12
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e.g., a balance between conflicting needs and goals. However, this does not mean that conflicts
over indirect/cumulative effects will necessarily be avoided by considering non-transportation
goals in the process.
The CEQ has outlined general goals (eleven principles) of ecosystem (biodiversity) management
(Figure III-2). CEQ suggests that these goals be considered by Federal agencies when assessing
the effects (direct, indirect, and cumulative) of their actions, including actions at the project-
specific or site-specific level. These goals are expressed through a number of Federal, state, and
local resource management plans (e.g., those for the North Carolina coastal area and various
river basins).
Relative to ecological goals, social or economic goals are typically not as well formulated or
articulated at this time, both generally and at the local level, e.g., in comprehensive or growth
management plans. While general principles of social impact assessment are being advanced,
goals are typically expressed in very broad terms, e.g., maintain community character or manage
growth, and will vary with location.
Proposed transportation improvements are often planned to support an area's economic
development goals. The desired economic growth is seen to be dependent upon the accessibility
improvements and increase in location attractiveness that the transportation project will bring.
In these cases, the plans demonstrate that development is "caused by the action" and is
"reasonably foreseeable," therefore the land use conversion and environmental effects associated
with that growth should be treated as indirect effects of the transportation project. Understanding
the economic development goals of communities in the study area should not only help
formulate the scope of the proposed transportation improvement, but will also help analysts
understand the nature of the induced indirect/cumulative effects.
While it is recommended that available plans be used to help determine the area's various goals,
several items should be kept in mind:
? Age of the Plan - In many areas there is no requirement for periodic updating of
comprehensive plans even where there is a formal planning process. Political winds tend
to change over time and a dated plan may not reflect the area's current needs and goals.
? Geographic Coverage of the Plan - Often, an incorporated area may have a
comprehensive plan and zoning while an adjoining unincorporated area does not. The
distinction between the incorporated and unincorporated area in terms of current land use
may not be clear. However, the absence of land use controls in the unincorporated area
may affect the character of future urbanization in the incorporated area. In addition, one
municipality's growth management plan may not conform to the overall plan for a region.
Section 111: Developing the Scope Page 111-13
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• Plan Preparers - It is important to know who was involved in plan preparation. For
example, whether or not the local citizenry has bought into a resources management plan
prepared by a non-local entity.
• Importance Ascribed to Plan - The degree of importance attached to the goals by the
public and their decision-making authorities is important in determining any potential
conflict between goals and impacts and in gauging the likelihood of plan enforcement or
change in the future.
Even in areas where there is an up-to-date plan and an effective planning process, it is probably
wise to use a public involvement method or methods to at least confirm the directions and goals
expressed in the plan, plus to gather information on the area's directions and goals first hand,
when appropriate. Moreover, certain methods can be used to flesh out alternative scenarios in
more detail than expressed in a plan. This greater level of detail may be needed for subsequent
indirect/cumulative effects assessment if issues are anticipated. Accordingly, the methods
discussion evaluates appropriate public involvement techniques for this step.
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Volume II: Practitioner's Handbook
FIGURE III-2
CEQ GOALS FOR ECOSYSTEM (BIODIVERSITY) MANAGEMENT
1. Take a "big picture" or ecosystem view;
2. Protect communities and ecosystems;
3. Minimize fragmentation, promote the natural pattern and connectivity of habitat;
4. Promote native species, avoid introducing non-native species;
5. Protect rare and ecologically important species;
6. Protect unique or sensitive environments;
7. Maintain or mimic natural ecosystem processes;
8. Maintain or mimic naturally occurring structural diversity;
9. Protect genetic diversity;
10. Restore ecosystems, communities and species; and
11. Monitor for biodiversity impacts, acknowledge uncertainty, and be flexible.
Source: CEQ, Incorporating Biodiversity Considerations into Environmental Impact Analysis Under the National
Environmental Policy Act, January 1993.
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The area's expressed goals give a part of the picture needed to understand potential
indirect/cumulative effects in a "big picture" context. It is also important to understand direction,
i.e., where an area has been, where it is, and where it is going. Direction can be understood in
part by identifying past, present, and anticipated socioeconomic, environmental quality, and land
development trends. Equally important is knowing the forces that have shaped landscapes,
economic activity, and land use patterns, e.g., transportation system, physical environment,
political, and market influences, and how the forces were influential (the same is true of existing
and anticipated forces).
Methods
Step 2A - Data Collection
The data collection task for this step should generally rely on readily attainable sources. The data
collection should not be viewed as an end in and of itself, but rather as a foundation for future
steps. Data for this purpose can be both quantitative and qualitative. Figure III-3 describes
potential sources of data regarding plans and trends. The checklists provided in Figures III-4
and III-5 are for use in identifying, organizing, and documenting directions and goals.
There are three general sources of data to be considered for this step:
? Local/Regional Trend Data - Recent and historical demographic data available from the
U.S. Census Bureau can be assembled in time series and used to identify trends in
population and household growth, location, and composition. Official projections
generated by state, regional, or MPO agencies should also be utilized whenever possible
as a source of information on future conditions. Profiles on trends in industry and the
regional economy can be generated from Census Bureau data (County Business Patterns)
or other government sources (Bureau of Economic Affairs). Data from local authorities
regarding annual building permit statistics and zoning variances or changes may also be
useful in identifying development trends.
? Land Use Plans/Comprehensive Plans - A variety of public and private entities may be
responsible for generating plans reflecting land use and community goals in the study
area. The full range of local and regional master plans, park and open space plans,
infrastructure plans, and economic development agency documents should be compiled
and carefully examined to gather information on the economic, social, and land use goals
of communities in the study area.
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Local/Regional Development Regulations - Development regulations currently in force in
the study area can be useful in determining community goals and isolating potential areas
of conflict as project impacts are identified. Zoning ordinances, special district
regulations, and development incentives/disincentives should be examined carefully.
Maps of the development regulation boundaries, especially digitized shapefiles for use in
GIS, may be useful in other aspects of indirect/cumulative effects analysis.
Section III: Developing the Scope Page 1114 7
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
FIGURE III-3
DESCRIPTION OF DATA SOURCES
FOR IDENTIFICATION OF GOALS AND TRENDS
Local Regional Trend Data
U.S. Census Data Recent and historical data on population and household growth,
race and ethnicity, income, age, and other important factors can be
obtained from the U.S. Census Bureau and assembled in time-series
for tracts, block groups, or other geographic areas making up the
study area to reveal trends.
State/Regional Growth Forecasts State planning agencies, MPOs or other regional planning
authorities are often responsible for generating 20-year growth
forecasts for areas under their jurisdiction. Official forecasts of this
type should be utilized whenever possible.
County Business Patterns Data and analysis on industry and economic trends assembled for
counties and groups of counties are available through the U.S.
Census Bureau.
BEA Industry Data The U.S. Bureau of Economic Analysis (Department of
Commerce), maintains time-series data on industry earnings and
employment at the county or MSA level. This data can reveal
important trends regarding the character of economic development
in the study area.
County/Local Building Permit Data Yearly data on issuance of building permits or certificates of
occupancy can be obtained from county or local authorities to
reveal trends on household growth and location.
Variance/Zoning Change History Public records of county or local authorities with responsibility for
granting zoning variances or adopting changes to zoning
regulations can be consulted to identify trends in the enforcement
and stability of land use regulations.
Land Use Plans/Comprehensive Plans
State and Regional Land Use Plans In some jurisdictions, state or regional authorities develop general
land use plans containing recommendations or regulations on
conservation areas and areas for residential, commercial, and
industrial development.
County/Local Building Permit Data In some jurisdictions, county agencies are responsible for land use
plans for the county as a whole or unincorporated areas. The plan
may identify goals and objectives for the future physical
development of the county with respect to public and private uses
of land or other natural resources with an aim of enhancement of
physical and economic conditions.
Local Land Use and Master Plans where local land use and master planning is conducted, plans
should be examined for descriptions of goals and anticipated future
conditions.
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Federal, Tribal, or State-owned Where study areas contain federal or state owned lands, care should
Property Master Plans be taken to examine plans for the use and expansion of parks,
wildlife areas, refuges, forests, and prisons. Development plans
for tribal areas are also important.
Park and Open Space Plans Counties, towns, and cities, may make plans for parks and other
open spaces and the management of this land for public enjoyment.
The plan can serve to refine and detail the park and environmental
corridor preservation recommendations set forth in state or regional
plans.
Farmland Preservation Plans In some jurisdictions, special plans regarding development and
conservation of farmland areas have been enacted.
Sewer/Water Service Area Plans In some jurisdictions, special plans have been developed to guide
future expansion of sewer and water utility services. Provision of
these services is often directly correlated with the potential for
higher density development.
Studies Done by Regional Planning MPOs or regional planning commission may have conducted
Commissions studies or may maintain databases of information regarding land
use plans, regulations, and trends.
Local Area Development/ In many jurisdictions, municipalities are authorized to prepare
Redevelopment Plans redevelopment plans for areas that substandard or unsanitary as a
result of inadequate planning, excessive land coverage, lack of
proper light, air, and open space, or other problems of age, or
physical deterioration.
Economic Development Agency Relevant state, regional, or local economic development agencies
Plans should be consulted for information regarding areas targeted for
development, future development incentives or other plans.
Economic Development Agency Relevant state, regional, or local economic development agencies
Plans should be consulted for information regarding areas targeted for
development, future development incentives or other plans.
Private Sector Plans Large private-sector land holders, such as corporations, developers,
private universities, or nature conservancies, may produce plans for
the development or management of their land holdings.
Transportation Corridor Plans An integrated transportation and land use plan may have been
prepared for other critical transportation corridors in the study area
that have high development potential.
Other Environmental Environmental documentation conducted recently for other
Documentation facilities or projects within the study area may be consulted for data
or leads for data sources.
Local /Regional Development Regulations
Zoning is an exercise of government power that regulates and
County/Local Zoning Ordinances restricts the use of private property in the public interest. Data on
zoning area boundaries and regulations are important for
determination of goals and application of further analysis
techniques.
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Official Maps Official maps illustrate government boundaries, zoning districts,
government lands, and street and highway facilities. Maps,
particularly those in digital form, are useful for overlay analysis
techniques.
Growth Boundaries In jurisdictions that have enacted urban growth boundaries, it is
important to obtain detailed information regarding boundary
locations, regulations, and future plans.
Annexation/Extraterritorial Zoning In jurisdictions where incorporated areas are allowed to exercise
zoning authority or annex areas outside their boundaries,
information should be gathered on regulations and future plans.
Coastal Regulations Development and use of coastal areas, floodplains, and wetlands
are often regulated by special statutes.
Local Highway Access Controls Access controls on local roadways within the study area but outside
the project area such as curb-cut regulations or arterial access
controls are relevant in analysis of goals and future development
potential
Special Development Districts Some jurisdictions may have special districts that regulate
development. Examples include urban redevelopment areas,
business improvement districts, planned unit development districts,
tax increment finance districts, and historic preservation districts.
TDR Sending/Receiving Zones Some jurisdictions have enacted regulations regarding the transfer
of development rights from restricted properties to properties where
development is encouraged.
Inclusionary Housing Incentives Some jurisdictions have enacted regulations and incentives to
encourage the development of low-income housing.
Easements and Deed Restrictions Easements and deed restrictions may determine the future
developability of a land parcel. Conservation easements, restricting
future development regardless of ownership, have been used
recently with more frequency.
Development Moratoria As part of the zoning authority in some jurisdictions, municipalities
or counties may declare a moratorium on development for a fixed
or limited time to allow for the completion of infrastructure or land
use regulations.
Impact Fees Some jurisdictions have imposed impact fees on developers to pay
for government capital costs necessary to serve development.
Adapted in part from: Indirect and Cumulative Effects Analysis for Project-Induced Land Development, Wisconsin
Department of Transportation, 1996
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FIGURE III-4
ORGANIZATION AND TABULATION OF GOALS CHART
Project Name:
(Check where applicable)
Location: Analyst: Date:
Social Health and Well-Being Goals
Achieve adequate, appropriate and
accessible open space and recreation
Comply with state and federal water and air
quality laws
Preserve or create multicultural diversity
Preserve heritage
_ Provide choice of affordable residential
locations
_ Provide urban environment for those with
special needs
Promote land use patterns with sense of
community
Provide a range of services accessible to all
Promote a healthy and safe environment
Provide sound management of solid and
hazardous waste
Other
Economic Opportunity Goals
Support activities to meet changing
economic conditions
Provide energy-efficient transportation
Provide developments with transit-supported
capabilities
Target economic export activities
Attract and maintain workforce
Promote infill of smaller, passed-over sites
Encourage redevelopment of older areas for
new purposes
Other
Ecosystem Protection Goals
- Protect ecosystems
- Minimize fragmentation
- Promote native species
- Protect rare and keystone species
Protect sensitive environments
- Maintain natural processes
Maintain natural structural diversity
- Protect genetic diversity
- Restore modified ecosystems
Other
Notes
Name Affiliation Date
Reviewed by:
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FIGURE III-S
STUDY AREA DIRECTIONS AND GOALS CHECKLIST
(Check where applicable)
Project Name: Location: Analyst: Date:
1. Generalized Setting
Within Metropolitan Statistical Area (Identify MSA) _
Outside of MSA _
Both Inside and Outside MSA Indicate Distance to Neatest Metropolitan Center -
2. Characteristics of Transportation System (Note: These items are not intended to cover entire transportation need but rather to use information from [note detailed
assessments to provide a preliminary indication of existing accessibility, service and [nodal interrelationship characteristics, i.e., factors relevant to subsequent indirect effects
analysis).
• Identify missing links in transportation system
• Map and describe existing level of service on minor and principal arterials and their access characteristics.
• Indicate distance to nearest interstate highway if not in study area.
• Map and describe existing transit routes and demand.
• Map and describe major concentrations of existing and planned development.
• Describe modal interrelationships including competing and complementary characteristics.
3. Population Trend Projection
Declining -
Static (± 1 %/10 years)
Slow Growth
Rapid Growth (>10%/10 years)
Entulovm ent Trend Projection
Declining -
Static (t1%/10 years)
Slow Growth
Rapid Growth (>10%/10 years)
4. Planning Context
Yes No If yes, identify by title, agency and date
Zoning -
State Master Plan -
County/Regional Master Plan -
Municipal Master Plan -
Growth Management Plan -
Water Quality Management Plan -
Other Natural Resources Management Plan -
5. For each plan identified in No. 3, summarize key goals, elements and linkages to other plans (specify, in particular, elements related to economic development, land
use development, the transportation system, and natural resource protection).
6. Describe any efforts to elicit local needs and goals from residents and/or agencies (source and result).
7. Describe known plans for major new or expanded activity centers including public facilities.
Is the activity center dependent on transportation system improvement? Yes - No -
8. Is the transportation need linked to economic growth and land development? Yes - No -
If yes, is the nature of the linkage to:
Serve the needs of planned growth or
Channelize growth or
Stimulate growth or
9. Based on information obtained, are there any apparent conflicts between transportation and other needs that could result in controversy? (Describe).
Yes Possible No
Reviewed by:
Name
Affiliation Date
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Step 2B - Public Involvement
Of course, it is important to deal with facts, particularly when facts are readily obtained.
However, facts tell only part of the story (or do not exist for all items of interest). Perceptions of
directions and goals or opinions about them can be valuable in establishing a "big picture"
context.
A number of public involvement techniques are advocated for obtaining the perceptions or
opinions. For example, the U.S. DOT document, Innovations in Public Involvement for
Transportation Planning (1996), is a notebook which outlines various practical techniques of
public involvement that can be used in a variety of situations. The reader should consult these
and other pertinent documents for details. A comparison of techniques relevant to goals
development includes:
? Visioning - This technique typically consists of a series of meetings focused on long-
range issues. It looks for common ground among participants in exploring and
advocating strategies for the future. With overall goals in view, it avoids piecemeal and
reactionary approaches to addressing problems. It accounts for the relationship between
issues, and how one problem's solution may generate other problems (e.g.,
indirect/cumulative effects). To be balanced, visioning requires involvement of all
stakeholders, and a cross-section of citizens. Resources required for visioning typically
include a staff leader committed to the process, a community participation specialist who
is well versed in the applicable subject matter, and staffers who can interpret and
integrate participants' opinions from surveys and meetings. If forecasts of information are
developed or if alternative scenarios are to be fleshed out, research and preparation time
can be extensive.
? Citizen Survey - This technique is used to assess widespread public opinion through a
survey administered to a sample group of citizens via a written questionnaire or through
interviews in person, by phone, or by electronic media. Surveys can be used to obtain
information for determining residents' perceptions of an area's future directions and
goals. Surveys can be informal or formal (scientific) with formal surveys being more
expensive and requiring a higher level of expertise. Survey respondents should be
selected to provide a composite view of the larger population. In this respect, a survey
can capture the views of those who are not ordinarily informed or involved in
transportation processes (including those who may not have the time to participate in
visioning or other public involvement initiatives). One drawback of the survey is that it is
not interactive.
? Focus Group - The focus group is another tool to gauge public opinion, and identify
citizen concerns, needs, wants, perceptions and expectations. A focus group is a small
group with professional leadership. Participants in a focus group are selected in two
ways: random selection to assure representation of a cross-section of society or non-
random selection to help elicit a particular position or point of view. A focus group can
help conform or deny established goals. A focus group is relatively inexpensive
compared with the costs and effort of administering a full opinion survey.
? Collaborative Task Force - A group of community leaders and private citizens could be
formed as a task force that would meet periodically throughout the process of
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indirect/cumulative effects analysis. The task force could provide direction and
consultation on the methods, assumptions and analysis results and serve as the first venue
for a visioning or focus group exercise.
A collaborative task force has these basic features:
- a sponsoring agency that is committed to the process;
- a task force formed of representative interests;
- emphasis on resolving an issue through task force consensus;
- detailed presentations of material and technical assistance for complete
understanding of context and subject matter; and
- serial meetings to understand and deliberate the issues.
A collaborative task force can require relatively significant resources. Among these are
an experienced, neutral facilitator; staff technical support; presentation materials
understandable to lay individuals; and, usually, specialized consultants. Several meetings
are likely, each consuming several hours.
Any public involvement effort should be inclusive and comprehensive. A proactive position
toward recruiting participants should be taken and every effort should be made to represent the
full range of community interests in visioning, focus groups, or surveys. The goals of low
income, minority or other traditionally disadvantaged populations must be considered along with
those who may be more active in the community. A list of those who may have valuable input
into the process includes those with knowledge of or interest in local land use decisions.
Section III: Developing the Scope Page III-24
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List of Potential Visioning, Focus Group, and Task Force Members
Municipal or County Legislative Members Community/Neighborhood Group Leaders
Mayors and County Executives Environmental Organizations
Tribal Leaders/Representatives Land Conservation Organizations
UFO Representatives Religious Leaders
Regional Planning Authority Business Owners and Executives
Representatives
Zoning/Planning Board Members
Local Transportation/Transit Officials
Public Safety Officials
Public Works Officials
Board of Education Officials
Economic Development Officers
Utility Representatives
Chamber of Commerce Representatives
Realtors
Bankers
Developers
Farmers
Building Managers/Business Park
Operators
Other Private Citizens
There is obviously some sensitivity involved in exploring the directions and goals of plans
developed by others. For this reason, visioning is often appropriate as a public involvement tool
in certain situations for determining or confirming the area's directions and goals for the future at
a broad level. Visioning can be used to develop alternative future scenarios for eventual
comparison to the proposed project scenario. The citizen survey or focus group techniques can
be used to support visioning when more details about directions and goals are required. Task
forces can be employed in more complex project circumstances.
Work Product for Step 2
The product of work for Step 2 consists of comprehensive lists (completed Figure III-4 and III-5
checklists, for example) detailing study area goals and trends. The lists can be used to support a
technical memorandum which synthesizes the study area's relevant plans, trends, policies and
shaping forces. The technical memorandum is suggested in more complex situations.
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Chapter 3
Step 3 - Inventory Notable Features
Overview
An inventory of baseline environmental conditions is another step of the scoping process, and is
typically done as a project proposal is being developed, usually prior to the NEPA class of action
determination. The typical inventory is fairly routine and the sources of data to undertake the typical
inventory are relatively well established. The baseline environmental inventory can be used as a tool
to identify notable features or specific valued, vulnerable, or unique elements of the environment.
Because indirect/cumulative effects analysis often involves a study area larger than that which may
be necessary for analysis of direct impacts, attempts should be made to incorporate consideration
of a study area for indirect/cumulative effects early in the planning or project development process.
An analysis of indirect/cumulative effects occurring after the initial screening effort should utilize
previous work on notable features, expanding the review to match study area boundaries or
modifying it to meet the needs of indirect/cumulative effects analysis as necessary. The objective
of this step is to identify specific environmental issues within the indirect/cumulative effects analysis
study area against which the project may be assessed.
This chapter will:
? discuss general considerations in developing an inventory of notable features;
? define the range of notable features relevant for inclusion in the inventory, including those
addressed by federal statutes;
? review data sources and methods useful in developing the inventory; and
? provide checklists useful in applying this step to practice.
Considerations
Whether from encroachment-alteration or project-induced growth, or in combination with other
actions, indirect and cumulative effects from transportation project change the environment. Society
has preferences for how much change is acceptable. The acceptability of the degree of change varies
depending on the affected setting or population. A number of terms are found in the literature that
describe settings or populations commonly afforded special attention with respect to change. The
Section III: Developing the Scope Page 111-27
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
term notable features is used in this handbook as an overarching term that encompasses the various
terms found in the literature. This term includes the following aspects of the human environment:
? Sensitive species and habitats - U.S. EPA uses terms such as sensitive species and habitats
noting that the term sensitive applies to ecologically valuable species and habitat, and those
vulnerable to impact. U.S. EPA added that rarity is often a good indicator of vulnerability.
(EPA, 1994) U.S. EPA notes other characteristics as being indicative of vulnerability as:
- species requiring high survival rates rather than high reproduction rates.
- species whose intrinsic rates of increase fluctuate greatly.
- communities with vulnerable keystone predators or mutualists.
? Valued environmental components - Irwin and Rodes (1990) use the term valued
environmental component as a "characteristic or attribute of the environment that society
seeks to use, protect, or enhance."
? Relative uniqueness, recovery time, unusual landscape features - Forman and Godron (1986)
use the terms relative uniqueness and recovery time as measures of a landscape element's
(ecosystem's) value. Relative uniqueness is "a measure of how many comparable examples
of this landscape element exist at different levels of scale, from the local area to the nation,
even the globe." Recovery time is "a measure of how long it would take to replace the
existing landscape element in comparable form if it were disturbed or destroyed." The
authors also note the importance of unusual landscape features, that is, "types of landscape
elements only found once or a few times across an entire landscape." Such features, e.g., a
single major river in a landscape, are notable as activity centers "where flows of species,
energy, or materials are concentrated."
? Vulnerable elements of the population - The field of social impact assessment also
recognizes vulnerable elements of the population (ICOGP, 1993). It has been suggested that
vulnerable segments of the population of a neighborhood or community include the elderly,
children, the disabled, and members of low-income or minority groups. Such segments may
be more at risk from the effects of air pollutant emissions (e.g., the elderly, children),
susceptible to changes in pedestrian mobility (the elderly, children, the disabled), or typically
under represented in providing input to transportation decisions.
What constitutes a notable feature depends on perspective (there are likely many other perspectives
or disciplines of study not discussed here that are captured by the term notable features). Therefore,
the inventory should cast as wide a net as possible on perspectives. Similarly, the definition of
notable features in an area depends on scale. What is notable to a region will often differ from what
is notable to a community or city. The various geographic scales should be examined in keeping with
the CEQ regulations which state that significance varies with context (40 CFR 1500-1508).
Section III: Developing the Scope Page III-28
Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
Methods
There are several basic steps in assembling an inventory of notable features and a variety of data
sources and basic methods to be utilized. To achieve optimum results in later steps of the
indirect/cumulative effects analysis process, every element considered here should be mapped using
GIS or other cartographic techniques. Subsequent steps in this analysis framework will benefit from
generation of overlay maps including notable environmental features, project design features, and
subarea boundaries. Basic procedures in this part of the indirect/cumulative effects assessment
framework include the following steps.
Step 3A - Assemble Inventory of Ecosystem Conditions
U.S. EPA's report on ecosystem approaches to highway impact assessment (1994) suggests several
ecosystem conditions to consider depending upon the setting (suburban, rural, or wildland). Figure
III-6 lists those conditions and provides a framework for documentation by the analyst. Data sources
for ecosystem conditions include:
? Nature Conservancy data, available through state Natural Heritage Programs (NHPs) or
Conservation Data Centers (CDCs), contain information on regional biological and
ecological features including rare species communities;
? U.S. Geological Survey(USGS) Biological Resources Division, consolidates information on
biological and ecological features from several Department of Interior bureaus;
? U.S. EPA Environmental Monitoring and Assessment Program (EMAP) has developed
detailed methodologies and indicators for assessment of baseline ecological conditions. This
program is currently in the implementation phase but information on select resources and
regions is currently available;
? state land management agencies;
? state fish, wildlife, and conservation agencies;
? state agricultural and forestry agencies; and
? tribal natural resource offices.
Step 3B - Assemble Inventory of Socioeconomic Conditions
Identification of features in the human social environment begins with an inventory of basic
socioeconomic conditions. Figure III-7 details basic economic, demographic, social, and physical
Section III: Developing the Scope Page III-29
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
conditions linked to notable features and provides a framework for their documentation. The
conditions outlined were drawn from the community impact assessment literature. (Pivo, 1992)
Data required for this step is similar to that required for Step 2 of the assessment framework (see
Chapter 2). Data gathering for the two steps should be integrated whenever possible. Potentially
useful sources of socioeconomic information are discussed below.
Published statistics - Existing measures and future projections of demographic and economic
factors in an area can be obtained from the following sources:
The U.S. Census provides data on population and household demographics, income,
education, housing type, journey to work, and length of residence in an area.
The number and type of jobs in a study area for current and historical periods may
be obtained through data on Covered Employment (ES-202) maintained by state
departments of labor and industry. The number of jobs divided by the number of
households in a study area determines the jobs/housing balance, a measure of self-
containment.
- In metropolitan areas, MPOs maintain data current employment and population
conditions as well as projections for future time periods which account for pending
and anticipated development projects.
? Other published material - Locally published sources may be relevant to the study. These
include:
- Local comprehensive plans (see Chapter 2) often include discussions of
socioeconomic conditions such as demographics and income; social conditions such
as crime rate and social organizations; and physical features, such as densities, form,
mix of land uses, and historic structures.
Historical studies of communities conducted by historical societies or local
universities may provide information on trends and conditions.
Newspaper articles may contain information on local conditions, features, and public
opinion.
? Interviews - Because of the age or incompleteness of statistics and local plans, it may be
necessary to conduct interviews with local government and planning officials to ascertain or
confirm information on social and physical conditions.
Section III: Developing the Scope Page III-30
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Public Involvement - Citizen surveys or focus groups can be useful in identifying what
residents like and dislike about the area, and where they would take visitors to give them a
feel for the area (uniqueness).
? Field Work - Field investigations may be necessary to confirm secondary source information
or to investigate items not identified through readily available information. Following
confirmation, the location and extent of inventoried items should be mapped and/or
tabulated.
Step 3C - Assemble Inventory of Notable Features
Notable features gleaned from investigations into ecological and socioeconomic conditions may be
documented using the framework given in Figures III-8 and I1I-9. Figure III-8 outlines the major
types of notable features. Figure III-9 was prepared to note that through enactment of laws, society
as a whole has in effect placed a value on certain resources or determined that certain resources
require special consideration before actions like transportation projects are undertaken. The table
lists pertinent federal laws; state and local transportation agencies should expand the list to include
pertinent state and local laws.
It is possible that a project study area could contain a number of possible notable features, and
differing views of what is notable or why it is notable. For these reasons, it is in a transportation
agency's interest to have as many interested parties as necessary involved in determining what are
notable features for a particular study area, especially when the study area is large in area or contains
many complex features.
? Collaborative Task Force - The collaborative task force public involvement technique is
ideally suited to consultation on notable features. Following data collection, the
transportation agency should assemble a preliminary list of notable features for potential use
as impact measures in the indirect/cumulative effects analysis. The same list could be used
for direct and cumulative impact analysis, as well. This list would form the basis of
discussion at a collaborative task force meeting(s). The final list of selected assessment
notable features should reflect the task force consensus.
Application to Practice
Transportation Systems Planning Context
An inventory of notable features is important in the planning of transportation systems because it
can help establish need (e.g., improving systems in lower income areas with poor access) and can
help planning agencies minimize potential conflict between the proposed systems and notable
Section III: Developing the Scope Page 111-31
Guidance on Indirect and Cumulative Impact Assessment Volume II.- Practitioner's Handbook
features. A notable features inventory at this stage of the transportation development process
considers features notable on a regional scale commensurate with the systems plan, typically a
metropolitan area or multi-county region. This inventory is typically less detailed than that suitable
for project evaluation (e.g, watersheds vs. individual streams, communities vs. neighborhoods).
Development of overlay maps or a GIS database indicating the location and extent of these major
socioeconomic and ecological features will help facilitate identification of potential direct, indirect,
and cumulative effects early in the process.
Project Evaluation Context
The methods and data sources discussed above are suitable for compiling an inventory of notable
features on a broad regional scale or a very local scale. At the project evaluation stage, generating
an inventory of features notable in each community or subregion of the study area is appropriate.
The step of determining the study area (see Chapter 1) will provide an indication of the level of
effort required and areas that will require particular attention.
Work Product of Step 3
The product from the work conducted during this step consists of documents completed in
accordance with Figures III-6 through III-9, with an accompanying map or GIS database illustrating
the location and extent of each notable feature, where appropriate.
Section III: Developing the Scope Page III-32
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Project Name:
Location: Analyst: Date:
Setting Describe/Characterize
(Map Locations)
_ Suburban
Landscapes
Remnant Communities
Greenways
Remnant Populations
Wetlands and Riparian Zones
Drainage Patterns
Natural Vegetation Diversity

_ Rural
Watersheds
Local Ecosystem Integrity
Riparian Corridors
Endemics and Migratory Species
Riparian and Forest Corridors
Hydrology
Landscape Pattern Diversity
Dispersal Routes

_ Wildland
Regional Ecosystems
Remote Habitat
Contiguous Habitat
Habitat Interior Species
Unique Environments
Structural Components of Interior
Habitat
Sub Population Movements

Reviewed by:
FIGURE III-6
ECOSYSTEM CONDITIONS INVENTORY
Name Affiliation Date
Section 111: Developing the Scope Page 111-33
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Project Name:
FIGURE III-7
SOCIOECONOMIC CONDITIONS INVENTORY
Location: Analyst:
Date:
Economic
Residents' occupational mix
Jobs in community (mix)
Jobs/housing balance (self-containment)
Income distribution mix
Journey to work (length and mode)
Job growth rate
Business ownership and services characteristics
Demographic
Population growth rate
Population age mix
Household types
Retired population percent
Social
Community cohesion
Crime rates
Clubs, sports and organizations participation
Education levels mix
Sense of control over change
Balance of old timers and newcomers
Physical
Housing stock mix and values
Open space percent
Town area and form
Separation from other activity centers
Residential density
Mix of land uses
Town edge activity
Historic structures and places
Circulation and traffic characteristics
Neighborhood design characteristics
Infrastructure character
Commercial building scale
Town entrance setting
Scenic character
Trees and vegetation presence
Noise levels and timing
Lighting influence
Describe/Characterize
Name Affiliation Date
Reviewed by:
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Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
Chapter 4
Step 4 - Identify Impact-Causing Activities
Overview
Steps 2 and 3 of the indirect/cumulative effects assessment framework have focused on the
identification of trends, goals, and notable features. The next steps in the framework involve
identification of impacts that may come into conflict with these goals and features. Gaining a
thorough understanding of features of the proposed project and other existing and proposed activities
and the range of impacts they may cause is the first step toward the identification of
indirect/cumulative effects. Project impact-causing activities are relevant to two of the three major
types of indirect/cumulative effects (see Volume 1, Section 4 for discussion of the major types of
indirect and cumulative effects):
? Encroachment-Alteration Effects - Effects that alter the behavior and functioning of the
physical environment are related to project design features but are indirect in nature because
they can be separated from the project in time or distance. These effects can be considered
cumulative in nature when they are additive over time or have an interactive (non-linear) net
effect on the environment.
Access-Alteration Effects (Project-Induced Growth) - Changes in traffic patterns and the
alteration of accessibility attributable to the design of the project can induce residential and
commercial growth in the study area. (Effects related to this induced growth constitute the
third type of indirect/cumulative effect and are attributable to induced growth itself, not
project design features. The factors leading to induced growth related effects will be
identified in subsequent steps in the framework.)
The key source of information regarding the features of the proposed project is the project
description. Typically, the transportation project description consists of basic information that
describes the facility to result from the proposed action or alternative, e.g., estimated year of
completion, type and function of facility, project length, termini, and access points, number of lanes,
etc. This is especially true in early project stages before detailed information becomes available from
preliminary design studies. It is clear from this study'sresearch findings that a more detailed project
description than is typical is needed to make indirect/cumulative effects more apparent earlier in the
project planning and development process.
The objective of this step in the framework is go beyond the typical project description to flesh out
those impact-causing activities that a project will entail. This is consistent with the overall
framework objective of promoting consideration of indirect/cumulative effects earlier in the
Section III: Developing the Scope Page 111-41
Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
transportation project development process. This is an exercise that occurs formally or informally
during the environmental impact assessment of a project. Research done in support of this indicates
that this exercise is typically done by the analysts who prepare the environmental consequences
section of the EIS, i.e., after preparation of the affected environment section of the EIS or later in
the process rather than sooner. However, as complete a description as possible of the proposed
action and alternatives early on, it is possible to begin the process of identifying cause-effect
relationships between activities and the context of the study area as defined by goals and notable
features.
In addition to the proposed action, cumulative effects analysis requires that other existing or
proposed activities in the study area that could affect the notable features described in Step 3 be
identified and evaluated. Activities of public agencies or private parties that may have adverse or
beneficial effects will be evaluated with the proposed action to determine the net effect on notable
features.
This chapter will:
? discuss considerations involved in gathering data on impact causing activities when project
specifications are not fully developed;
? outline the major types of impact-causing activities;
? describe attributes of transportation projects that lead to access alteration effects; and
? provide a framework for documentation of other actions and impact-causing activities.
Considerations
A transportation project may involve a number of impact-causing activities. Few details may be
known about these activities at the early stages of project planning or development beyond the basic
project design concept and scope. Therefore, this step may require some leaps of faith by those
developing the description, as well as an understanding that the information provided is for purposes
of conceptualizing, not quantifying, effects. In other words, what is important at this point is
identification of the types of activities that the project will entail. This step can be accomplished
with a level of detail commensurate with 400-scale mapping (or similar).
An understanding of the NCDOT's past practices in similar situations, e.g., bridging of streams
versus placing a stream in a culvert, as well as knowledge of relevant sections of the agency's design
manual and standard specifications is needed. Some experience is necessary to make judgements on
these items.
Section III. Developing the Scope Page 111-42
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
The project description should also be viewed as a piece that will evolve, and should be updated as
details about the project become known with more certainty. In particular, the linking of impacts
and goals/notable features in Step 5 (see Chapter 5) should prompt development of more details on
activities that have potential for significant impact, where such details are lacking.
Detailed information regarding other actions in the study area may not be available and would not
be necessary for an evaluation of cumulative effects. Rather, the goal is to identify a general stress
level on affected resources associated with other activities so that it is possible to determine whether
the resources, ecosystems, and human communities of concern are approaching conditions where
additional stresses will have an important cumulative effect. (CEQ,1997) Once this is determined,
the effects of the proposed action may be evaluated in context.
Methods
Figure III-10 provides a matrix suitable for documenting other activities that may cumulatively affect
notable resources in the study area. Significant existing and proposed activities can be identified
during the data gathering and review of community and agency plans necessary for identification
of trends and goals (Step 2) and notable features (Step 3). Where activities contributing to
cumulative effects are not well defined, a general stress level can be described. For example,
individual farms or manufacturing plants need not be identified, but the presence of, or plans for,
substantial agricultural or industrial activity should be noted.
Figure III-11 presents a checklist developed from the literature (Leopold, 1971) that can be used to
help flesh out typical impact causing activities of transportation projects. This checklist may also be
used to document impact causing activities associated with other projects or actions in the study area.
For a given project, pertinent impact-causing actions can be viewed as potential catalysts for
indirect/cumulative effects.
Available project and plan information should be consulted to complete the checklist. The question
for the analyst is does the tabulation provide sufficient information about the breadth, duration,
location, and type of activity such that the general types of impacts to be expected from the project
can be inferred. If not assumptions will need to be made based on standard practice, as discussed
above.
If there is a substantial difference between an assumption and the detail developed at a later time
regarding a particular activity, (e.g., use of fill material rather than structure) then an assessment
needs to be made of whether or not the difference causes a substantial change in either the
identification of potentially significant indirect/cumulative effects (Step 5), the analysis of the effects
(Step 6), or the conclusions regarding the acceptability of the effects (Step 8). This assessment can
be done using the sensitivity analysis or risk analysis task described in Step 7.
Section 111: Developing the Scope Page 111-43
Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
FIGURE III-10
OTHER ACTIVITIES (EXISTING AND PROPOSED) THAT MAY
CUMULATIVELY AFFECT NOTABLE FEATURES
Description/Responsible Location Status Type of Potential Conflict
Party (Deserae-Map) ( s1Prwfed) with Notable Feature
Residential
IndustriaUCommercial
Government/Community Facility
Utilities
Transportation
Other
Project Name: Location: Analyst: Date:
Section III: Developing the Scope Page III-44
Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
The general types of project impact causing activities include:
? Modification of Regime - alteration of habitat, flora, hydrology, and other features;
? Land Transformation and Construction - construction method, ancillary elements;
? Resource Extraction - excavation and dredging;
? Processing - storage of supplies;
? Land Alteration - landscaping, erosion control;
? Resource Renewal Activities - remediation, reforestation;
? Changes in Traffic - traffic patterns on project and adjoining facilities;
? Waste Emplacement - landfill, waste discharge;
? Chemical Treatment - fertilization, deicing; and
? Access Alteration - changes in access, circulation patterns, travel times to major attractors.
Transportation projects that produce a significant change in accessibility between major
nodes of employment, housing, and commercial development can make an area more
attractive to development. Basic information regarding a project's propensity to change
accessibility can help analysts gauge whether this effect merits investigation. Changes in
accessibility imply changes in travel demand and travel patterns. Modeling of travel demand
in transportation systems has been common practice for decades, and is required by federal
regulations in urbanized areas. In modeling practice, a project (or change in the system)
needs to be of a certain size to produce a measurable change in travel demand or travel
patterns. Therefore, it follows that only those projects that could produce a measurable
change in travel demand or travel patterns (and, thus, accessibility) need to be examined for
indirect and cumulative effects in the transportation system context (regardless of whether
the project is in an urbanized area or a rural area).
Section III. Developing the Scope Page III-45
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
FIGURE III-11
PROJECT IMPACT-CAUSING ACTIVITIES CHECKLIST
Project Name: Location: Analyst: Dace:
If Yes,
Yes No Describe Generally (Source, Breadth, Duration, Location and Type)
Modification of Regime
Exotic Flom Introduction _
Modification of Habitat
Alteration of Ground Cover _
Alteration of Groundwater Hydrology -
Alteration of Drainage -
River Control and Flow Modification
Channelization
Noise and Vibration
Land Transformation and Construction
New or Expanded Transportation Facility -
Service or Support Sites and Buildings -
New or Expanded Service or Frontage Roads -
Ancillary Transmission Lines, Pipelines and Corridors -
Barriers, Including Fencing -
Channel Dredging and Straightening -
Channel Revetments
Canals -
Bulkheads or Seawalls
Cut and Fill
Resource Extraction
Surface Excavation _
Subsurface Excavation _
Dredging -
Processing
Product Storage -
Land Alteration
Erosion Control and Terracing -
Mine Sealing and Waste Control -
Landscaping
Wetland or Open Water Fill and Drainage -
Harbor Dredging -
Resource Renewal
Reforestation _
Groundwater Recharge -
Waste Recycling
Site Remediation
Changes in Traffic (including adjoining facilities)
Railroad _
Transit (Bus) -
Transit (Fixed Guideway) -
Automobile
Trucking _
Aircraft _
River and Canal Traffic _
Pleasure Boating -
Communication _
Operational or Service Charge -
Waste Emplacement and Treatment
Landfill _
Emplacement of Spoil and Overburden -
Underground Storage _
Sanitary Waste Discharge -
Septic Tanks -
Stack and Exhaust Emission
Chemical Treatment
Fertilization _
Chemical Deicing -
Chemical Soil Stabilization
Weed Control -
Pest Control -
Access Alteration (see Figures 43 and 4-4)
New or Expanded Access to Activity Center -
New or Expanded Access to Undeveloped Land
Alter Travel Circulation Patterns _
Alter Travel Times between Major Trip Productions
and Attractions _
Alter Travel Costs between Major Trip Productions
and Attractions
Others
Name Affiliation Date
Reviewed by:
Section III: Developing the Scope Page III-46
Guidance on Indirect and Cumulative Impact Assessment Volume IL• Practitioner's Handbook
Application to Practice
Transportation Systems Planning Context
Major existing and proposed activities with the potential to impact notable features can be identified
through a review of agency plans (regarding land use, transportation, capital improvement, resource
management) and existing land use, environmental, and socioeconomic conditions in the study area.
A thorough accounting of baseline existing and future conditions will provide the context for
evaluation of indirect and cumulative effects.
For the proposed plan, the general attributes of each component or mode should be described in as
much detail as possible using Figure III-11 as a guide. These descriptions would be based on
assumptions derived from standard practice, previous experience or professional judgment. The
location of potential impact causing activities should also be described in a general manner.
Project Evaluation Context
Features of the proposed project and other actions that may result in impacts should be described
with as much specificity as possible with assumptions substituted for detailed information as
necessary. A list should be made of assumptions used to fill in gaps where details about activities
are lacking. This list should be consulted and updated as details are developed but no less frequently
than the inception of each subsequent step of the indirect/cumulative effects assessment process.
Work Product of Step 4
The product of this step consists of a list of other existing and potential activities in the study area
that may affect notable features (completed Figure III-10) and a list (completed Figure III-11
checklist) of the impact-causing actions of the proposed action or other actions, in as much detail
as possible.
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Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
This Page is Intentionally Left Blank.
Section III. Developing the Scope Page III-48
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Chapter 5
Step 5 - Identify Potential Indirect/Cumulative Impacts for Analysis
Overview
Once the features of the proposed project and the baseline conditions of the study area have been
established, effects that require detailed analysis may be identified. The objective of Step 5 is to
compare the lists of impact-causing activities developed in Step 4 with the inventory of goals, trends
and notable features that make up the baseline conditions identified in Steps 2 and 3. The
comparison is designed to explore potential cause-effect relationships; and to establish which effects
merit subsequent detailed analysis or, conversely, which effects are not potentially significant and
require no further assessment.
This chapter will:
? Describe the range of indirect/cumulative effects related to encroachment alteration,
including ecological and socio-economic effects.
? Describe three types of induced growth effects: effects from projects planned to serve
specific land development; effects from projects likely to stimulate complementary
development; and effects from projects likely to influence intra-regional land development.
? Summarize qualitative and quantitative methods that can be used to identify
indirect/cumulative effects.
? Present considerations and a set of questions in decision tree format for assessing the
significance of identified effects.
Considerations
The discussion of general issues is organized by the three basic types of indirect/cumulative effects:
encroachment-alteration/single source additive or interactive effects; induced growth effects; and
effects related to induced growth/multiple source additive or interactive effects. Potential effects in
each of these categories should be considered for their relevance to the project and significance in
the study area. A discussion of the methods and criteria available for determining relevance and
significance of effects follows.
Section III: Developing the Scope Page 11149
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Encroachment-Alteration/Single-Source Additive or Interactive Effects
Alteration of the behavior and functioning of the affected environment caused by project
encroachment can be characterized into two broad categories: ecological effects and socioeconomic
effects. These effects can be linked to project impact causing activities identified in the previous
step. The two main effect types are discussed below.
Ecological Effects
The ecosystem approach embodied in CEQ's biodiversity document (1993) recognizes the
"fundamental interconnections within and among various levels of ecological organization."
Ecological organization is a hierarchically arranged continuum as illustrated in Figure III-12.
Reduction of diversity at any level will have effects at the other levels. Therefore, an understanding
of the interconnections can help reveal the chain of events delayed in time or space from the original
transportation project action or disturbance on or within a particular level of ecological organization.
The interconnections in ecosystems are numerous and complex. Many ecological communities are
constantly changing. However, there is a certain range of possibilities that help define a given
community. In the absence of a major disruption, species composition and relative abundance in a
community can be expected to vary within definable boundaries, perhaps cyclically or perhaps
randomly. Disruption of such systems, e.g., the introduction of contaminants, creates new
boundaries, changing the range of possibilities in ways that are not always predictable.
Transportation corridors a have unique impact on ecosystems associated with their linear form.
These corridors may function as specialized habitats, conduits of movement, barriers or filters to
movement, or sources of effects on surrounding habitats. Improvements within corridors can have
consequences to habitats removed in time and distance from the project. Together with other human
actions, the cumulative effects can be significant.
The following indirect and cumulative effects of transportation project actions can have important
consequences for ecosystems (see Figure 111-13):
? Habitat fragmentation from physical alteration of the environment;
? Lethal, sublethal and reproduction effects from pollution;
? Degradation of habitat from pollution;
? Disruption of ecosystem functioning from direct mortality impacts; and
Section 111: Developing the Scope Page 111-50
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
? Disruption of natural processes (e.g., hydrology, species competition, predator-prey relations,
etc.) from altered energy flows.
The ability of an ecosystem to respond to a disturbance or perturbation from a transportation project
is a function of its resistance (the ability of the ecosystem to withstand or resist variation imposed
by disturbance or perturbation) and recovery (the ability of an ecosystem to respond after being
changed). Note that different elements of an ecosystem will have different rates of resistance and
recovery which also interact with each other.
Section III: Developing the Scope Page 111-51
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
FIGURE III-12
COMPONENTS OF BIOLOGICAL DIVERSITY
• Regional ecosystem diversity: The pattern of local ecosystems across the landscape,
sometimes referred to as "landscape diversity" or "large ecosystem diversity".
• Local ecosystem diversity: The diversity of all living and non-living components within a
given area and their interrelationships. Ecosystems are the critical biological/ecological
operating units in nature. A related term is "community diversity", which refers to the variety
of unique assemblages of plants and animals (communities). Individual species and plant
communities exist as elements of local ecosystems, linked by processes such as succession and
predation.
• Species diversity: The variety of individual species, including animals, plants, fungi and
microorganisms.
• Genetic diversity: Variation within species. Genetic diversity enables species to survive in a
variety of different environments, and allows them to evolve in response to changing
environmental conditions.
The hierarchical nature of these components is an important concept. Regional ecosystem patterns
form the basic matrix for, and thus have important influences on, local ecosystems. Local ecosystems,
in turn, form the matrix for species and genetic diversity, which can in turn affect ecosystem and
regional patterns.
Relationships and interactions are critical components as well. Plants, animals, communities and other
elements exist in complex webs, which determine their ecological significance.
Section III: Developing the Scope Page 111-52
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Socioeconomic Effects
Encroachment by transportation projects can directly affect the physical nature of a neighborhood
in two major ways:
? alteration of traffic patterns and access; and
? relocation of homes and business, or relocation or alteration public facilities.
These direct effects can result in indirect/cumulative effects that can be magnified by the cumulative
impacts of other actions. These effects include alterations to:
? neighborhood cohesion;
? neighborhood stability;
? travel patterns of commuters and shoppers;
? recreation patterns at public facilities;
? pedestrian dependency and mobility;
? perceived quality of the natural environment;
? personal safety and privacy; and
? aesthetic and cultural values.
These variables should be used to explore effects of changes in the physical environment from
transportation projects. For example, a highway project can physically alter the local street network
and/or increase traffic volumes on local streets, both of which could effect pedestrian mobility and
consequently, interactions and neighborhood satisfaction.
The categorization of effects on the environment presented in Figure III-14 can be a useful tool for
identifying socioeconomic indirect/cumulative effects. Of particular note is the opportunity-threat
category of effects, i.e., those that can occur while a project is planned but before construction.
Examples include effects on real estate investment and maintenance of property. Such effects may
indicate the long-term indirect/cumulative effects that can be expected once a project is
implemented.
It is important to note that the ecological and socio-economic encroachment-alteration effects
described above can also arise from induced growth which is itself an indirect effect. Induced
growth effects are described below.
Section 111: Developing the Scope Page 111-54
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
FIGURE III-14
CONCEPTUAL APPROACH TO EFFECT IDENTIFICATION
Temporal Phase
System Affected Opportunity-Threats Development/Event Adaptation/Post-
Development
Physical Anticipatory construction Potential massive Creation of development-
or lack of maintenance, alteration of the physical specific facilities,
decay of existing environment, construction deterioration of alternative
structures and facilities. of new and upgrading of productive facilities,
existing facilities. destruction of
environment.
Cultural Initial contact, new ideas, Suspension of activities Gradual erosion of culture:
potential for loss of that assure cultural loss of unique knowledge,
cultural continuity. continuity (e.g., skills, and/or perspectives.
subsistence harvest).
Social Organizational changes; Population increase, influx Gradual loss of social
investment of time, of outsiders: decline in human capital (e.g.,
money, or energy for density of organizational networks
support or resistance; acquaintanceship: social and skills, replacements
differences in change. having limited optional
interpretation of risk. application).
Political/Legal Litigation to force or Intrusion of development Zoning and regulatory
block proposed activity into community changes in search of new
development, heightened politics, litigation and development, new
political claims-making. conflict over activity laws/ruling in response to
impacts. impacts.
Economic Decline or increase in Traditional boom/bust Loss of economic
property values, effects, inflation, entrance flexibility, specialization
speculation, investment. of outsiders into local of business.
labor market.
Psychological Anxiety, stress, anger: Stress associated with Acquisition of coping
gains or losses in rapid growth, psycho- strategies that are
perceived efficacy. social pathology, loss of potentially maladaptive
efficacy. under future scenarios.
Source: Gramling and Freudenberg, p. 218.
Section III. Developing the Scope Page 111-55
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Induced Growth Effects
Transportation improvements often reduce the time-cost of travel, enhancing the attractiveness of
surrounding land to developers and consumers. Development on vacant land, or conversion of the
built environment to more intensive uses, is often a consequence of highway and transit projects.
Growth in population and employment attributable to a direct project effect (change in accessibility)
is an indirect effect that, in turn, produces its own effects on the environment.
Important characteristics of induced growth are described below and illustrated in the attached
figures:
The land-use impacts of highway investment vary depending on existing land-use conditions
in the project area (see Figure III-15).
Transportation investments can prompt changes in economic, social, and demographic
conditions which can alter location decisions and land use (see Figure I1I-16).
? A transportation investment and the increased accessibility that it brings is just one factor in
the development decision-making process (see Figure III-17). Other factors include:
location attractiveness (physical features; suitability for development; land price and
development costs; adjacency to markets, customers, and demand generators);
- consumer preferences (for local features, existing/anticipated development);
the existence/availability of other infrastructure (water, sewer, communications);
local political and economic conditions (tax rates, incentives, regulatory
environment, availability of labor and capital); and
the rate and path of urbanization in the region.
Induced growth effects fall into three general categories: effects of projects planned to serve specific
land development, effects of projects likely to stimulate complementary development, and effects
of projects likely to influence interregional locational decisions. These induced growth types are
discussed in detail below.
Section III: Developing the Scope Page III-56
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Projects Planned to Serve Specific Land Development
Transportation projects designed specifically to serve existing or planned large land development
projects or groups of projects require a thorough analysis of induced growth and related effects. This
is because:
? land development is not just probable but highly likely;
? the magnitude and timing of the development are known or generally predictable; and
? details of development projects are known and can be analyzed for environmental effects.
Since the land development projects are known, analysis of this type of growth is of importance to
indirect/cumulative effects analysis. With details about development in hand, analysis will focus on
impacts related to the magnitude and timing of development than its probability of occurrence.
Section III: Developing the Scope Page 111-57
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Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Projects Likely to Stimulate Complementary Land Development
Complementary land development, such as highway-oriented businesses (e.g., gas stations, rest
stops, motels), is more likely near interchanges in rural areas where property values were originally
low. Interchanges in suburban or urban areas where property values were higher before project
planning and implementation are more likely to support a greater proportion of higher density uses,
as well as a greater mix of uses. Factors influencing the likelihood and rate of development near
rural interchanges include:
? distance to major urban area or regional center (proximity corresponds to higher probability
of development - see Chapter 6, Figure N-5 for examples of traffic volumes and
corresponding levels of development);
? traffic volume on the intersecting road (higher volumes correspond to higher probability of
development - see Chapter 6, Figure N-5 for examples of traffic volumes and corresponding
levels of development);
? presence of frontage road (greater potential for intensive development); and
? availability of water and sewer and other infrastructure (greater potential for development).
If these factors are present, induced growth effects of this type warrant analysis.
Common patterns of development:
? Interchange quadrants on the right-hand side of motorists approaching the interchange from
the main road have higher visibility and are often developed first.
Transit projects with stops in suburban or urban areas may produce higher density
commercial and residential uses and complementary retail and service development such as
coffee shops, dry cleaners, and newsstands.
Projects Likely to Influence Intraregional Location Decisions (Development Shifts)
Apart from the complementary development described above, on a regional basis, the impact of
highway and transit projects is generally minimal. The localized effect of such projects on land use
can be substantial, however. If the conditions for development are generally favorable in a region,
i.e., the region is undergoing urbanization, then highway and transit projects can become one of the
major factors that influence where development will occur, and project-induced growth warrants
evaluation.
Section III: Developing the Scope Page 111-61
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Where transportation projects do influence land development, the general tendency is toward
relatively high density commercial or multi-family residential development near facility nodes in
urban and suburban areas and single-family residential development in the urban fringe.
Development effects are most often found:
? up to one mile around a freeway interchange;
? up to two to five miles along major feeder roadways to the interchange; and
up to one-half mile around a transit station.
General circumstances influencing the likelihood of induced development shifts include:
? Extent and maturity of existing transportation infrastructure - The influence of highway
projects diminishes with successive improvements because each new improvement brings
a successively smaller increase in accessibility.
? Land availability and price - Development cannot take place without the availability of land
of a quality and price suitable for development. Property values are de-facto indicators of
the potential for land use change because investment decisions revolve around market prices.
Land prices are likely to reflect a parcel's suitability for development (favorable topography),
the availability of other suitable parcels in the area, the attractiveness of the location and
many of the other factors listed below. An abundance of suitable, low priced land maybe
indicative of potential development if other factors are present. A scarcity of land or high
price does not necessarily indicate a lower probability of development, however. If other
factors described here are favorable, high density development may occur where land is
scarce or high priced.
? State of the regional economy - Even if changes in accessibility are great, development is not
likely to occur if the regional economy will not support new jobs and households, if credit
or financing is not readily available, or if firms conclude that the availability of labor,
suppliers, or local markets for goods, are not sufficient.
? Area vacancy rates - High local vacancy rates in housing or commercial space of good
quality may be absorbed before any shift in development to the project area is seen.
? Location attractiveness - The quality of existing development, local politics, growth history,
are all factors considered in addition to transportation availability and cost.
Section 111: Developing the Scope Page 111-62
Guidance on Indirect and Cumulative Impact Assessment Volume H.- Practitioner's Handbook
? Local political regulatory conditions - Low business, property and sales tax rates, the
availability of incentives for development such as tax abatements, and a regulatory
environment that is favorable to business are factors favorable to development. The speed
ease, or predictability of the development review process can also impact development costs
and is a factor to be considered.
? Land use controls - Development is shaped by zoning ordinances and other land use controls
that influence the amount of land available for various uses, the densities permitted, and the
costs of development. Pressures for development can prompt communities to alter land use
controls, however, and an evaluation should be made which considers the likelihood that
changes in land use controls will occur. Such an evaluation can consider the historical record
of zoning enforcement and granting of variances, whether the controls are rooted in long
range comprehensive plans, and the existing amount of undeveloped land for each use.
If these conditions are favorable for development, a detailed analysis of induced growth and its
potential for impact on important area goals or notable features is warranted.
Review of recent indirect/cumulative effects case law (See 4.0 Case Law, Section I, Volume 1)
suggests that analysis of induced growth effects is required whenever economic development is cited
in the statement of purpose and need for the project.
Effects Related to Induced Growth/Multiple Source Additive or Interactive Effects
Project-induced land development and growth can affect the environment in many possible ways.
A general tabulation of possible land development effects in terms of economics, the natural
environment, aesthetic and cultural values, and public and private services is presented in Figure
III-18. A tabulation of possible socioeconomic effects of land development is presented in Figure
III-19. Obviously, the degree of certainty, specificity, and need to know about the induced effects
will determine the extent that the corresponding related effects should be examined.
One particular effect related to induced growth, the effect of transportation investments on air quality
vis-a-vis land use change, has come to the forefront in recent years. From the above discussion, it
is clear that transportation investments influence land use under certain circumstances. Empirical
data suggests that transportation investments worsen per capita emissions when they support
development at the urban fringe, i.e., the location where the lowest density and highest travel
consumption are found. From this it is inferred that transportation investments will improve per
capita emissions when they create arrangements of land uses that require less vehicular travel.
Section III: Developing the Scope Page III-63
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
However, the relationship between travel and land use is complex. For example, income accounts
for a portion of travel variability with land use. In addition, insufficient data is available to determine
causality, e.g., whether low density residential development "causes" people to have more vehicle
travel or whether people with a proclivity toward extensive auto mobility select low density areas
for living. Regardless, the general interrelationships among transportation investment, land use, and
air quality merit exploration particularly for those plans or projects that involve the urban fringe
(generally high land availability/low land prices in an urbanizing area).
Section III: Developing the Scope Page 111-64
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
FIGURE III-19
POSSIBLE EFFECTS OF LAND DEVELOPMENT
ON SOCIOECONOMIC VARIABLES
1 LAND DEVELOPMENT
I NEW
• Diversity in amount and type of employment
activities
• Seasonality of economic activities
• Property values
• Distribution of personal wealth
• Fiscal expenditures for municipal services
• Municipal revenues
• Form of buildings: height and width
• Landscaping and topographical features
• Supply, location and densities of buildings
• Supply and location of functions of buildings:
- residential (single-family, multi-family, etc.)
- commercial
- recreational
- industrial
• Supply and spatial distribution of open space an(
greenery
• Traffic volumes
• Noise levels
• Air quality
At Community Scale
• Demographic Characteristics
- age, sex characteristics
- migration characteristics
- displacement of residents
- racial, ethnic characteristics
• Institutional Membership
- civic groups
- religious groups
- social clubs
- political groups
• Residential Patterns
- supply and distribution of various housing types
- segregation of social, racial, ethnic or income
groups
• Uses and Perceptions of Services
- recreation
- shopping
- mass transit
- schools
- health care
• Perceptions of Environmental Quality
• Perceptions of Personal Safety and Privacy
• Political Power
- membership in dominant decision-making groups
- elected officials
At Neighborhood Scale
• Demographic Characteristics
- age, sex characteristics
- migration characteristics
- displacement of residents
- racial, ethnic characteristics
• Uses and Perceptions of Services
- recreation
- shopping
- mass transit
- schools
• Recreation Uses and Perceptions in Informal Space
around Home
• Pedestrian Mobility
• Perceptions of Environmental Quality
• Perceptions of Personal Safety and Privacy
• Aesthetic Preferences
- visual attractiveness
- view opportunities
- historical resources
Section III: Developing the Scope Page 111-68
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
Methods
There are a number of techniques discussed below that could support identification of cause-effect
linkages between project impact-causing actions and goals and notable features. The techniques can
be used individually or in combination. The techniques involve varying degrees of background
research.
? Matrices - A project evaluation matrix is commonly a grid diagram in which two distinct lists
are arranged along perpendicular axes, e.g., actions and environmental characteristics. The
interaction between actions and their environmental characteristics are noted in the matrix.
Notation can be made in one of the following forms:
- Binary Notation: Only the presence or absence of an effect is indicated in the matrix through
use of a checkmark or other device. This approach is the most straightforward and
understandable but does not allow for notation of the magnitude of the impact or recognition
of the importance of the resource relative to others in the matrix.
- Quantitative Notation: The magnitude, importance, duration, probability of occurrence,
feasibility of mitigation, or other factors relating to the impact could be quantified and noted
in the matrix. This method of notation requires a measurable quantity for all impacts.
Differences in units used to measure various impacts must be clearly noted. Such differences
may make it difficult to compare impacts.
- Weighted Notation: Relative ranking of impacts on a common scale allows would allow for
comparison of impacts, including summation into an overall ranking. A weighting scheme
may also be designed to take the relative importance of each impacted resource into account.
Weighting schemes may be subjective in nature especially when comparing the value of
impacted resources in relation to each other--the methods and criteria employed should be
thoroughly reviewed and documented.
While a variety of techniques may be employed to identify indirect/cumulative effects in
addition to matrices, the final product of this step in the framework should be completion of the
Evaluation Matrix attached as Figure III-22.
? Networks - Also known as system diagrams, networks can be used in classifying, organizing,
and displaying problems, processes, and interactions and to produce a causal analysis of the
indirect/cumulative effects situation. Obviously, the network is only as good as the as the
underlying understanding or assumptions of often complex processes and interactions. Networks
often assume a strict hierarchical relationship among variables that may simplify more complex
interrelationships. Network diagrams can include quantitative data in a fashion similar to the
methods of notation describe for matrices. Information regarding probabilities may also be
noted on network linkages and multiplied as one moves down the effects chain to reach the
probability of tertiary effects.
Section 111: Developing the Scope Page 111-69
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
The chains of indirect/cumulative effects illustrated in Figures III-20 and III-21 may be used as the
basis for development of either matrices or networks suited to a particular project. Figure III-17
provides an illustration of simple network diagram.
? Qualitative Inference - This technique involves a case study description of an area of concern,
e.g., habitat or neighborhood, and an identification based on professional judgement of the
possible changes that the proposed project would entail. The case study should focus on the
elements or indicators that characterize the area of concern using ecological, economic,
demographic, or social profile information from the baseline investigations in Steps 2 and 3.
This technique, though practical and simple, has obvious limitations. Foremost among these is
slipping into speculation based on limited data or unusual circumstances. Broad participation,
including input from local planners, experts, or other stakeholders through surveys, interviews,
or task forces can help avoid speculation.
? Comparative Case Analysis - Effects attributable to previously completed projects of a similar
nature in similar circumstances can be studied for their applicability to the project under
consideration. This comparative technique is described in detail in Chapter 6. Because it is
difficult to find cases that are comparable in every respect, care should be taken not to rely
exclusively on a comparative case for identification of effects. This technique can be a valuable
supplement to other techniques outlined here.
? Cartographic Techniques - Specific techniques, like the McHarg overlay technique (1969)
which involves the combination of various feature and resource maps, are time-tested. These
can be particularly useful for visualizing potential indirect/cumulative effects related to
alteration of the physical environment, e.g., habitat fragmentation or community segmentation.
Computerized geographic information systems have greatly enhanced the ability to process and
display cartographic information. Cartographic techniques are limited in their ability to reveal
the structure, function, and dynamics of areas. However, their utility can be expanded by relating
inventoried information about these characteristics via a relational database.
Another cartographic technique applicable to identification of indirect/cumulative effects is
resource capability analysis (Rubenstein, 1987). Similar to the overlay technique, this process
involves the preparation of two maps an opportunity map depicting conditions favorable to
development (topography, soil types) and a constraint map depicting areas unsuitable for
development (wetland, floodplains or other notable features identified in Step 3). Overlaying
the two maps produces a land suitability map indicating areas with capacity for potential
induced growth. This map could be further modified to indicate areas with the highest potential
for complementary development (interchange quadrants) and development shifts (interchanges
and feeder roads) under the action alternatives.
Section III: Developing the Scope Page 111-70
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Application to Practice
It is likely that some combination of the methods outlined above will be needed in most situations
to identify the proposed transportation project's indirect/cumulative effects. This combination would
include cartographic techniques for spatial analysis; matrices or networks for visualizing systems'
functions, behavior, and interconnections with the project; and either qualitative inference or
comparative case study to support the visualization. Further considerations for systems planning or
project evaluation are discussed below.
Transportation Systems Planning Context
All of the methods outlined above are applicable to the identification of indirect/cumulative effects
in the systems planning stage of the transportation development process. Effects identified in this
stage are necessarily broader in nature because project design details are not fully developed.
Induced growth and related effects arising from area-wide increases in accessibility will, therefore,
tend to be the focus of investigation.
An example of how methods can be combined to identify the full range of indirect/cumulative effects
discernable in the planning stage is given below.
? A simple matrix with binary notation can be drafted using professional judgement or lessons
drawn from a review of the literature or similar cases encountered in the planning agency's
jurisdiction or other areas. The matrix will show the range of potential indirect/cumulative
effects that can arise out of impact causing activities identified during Step 4 (see Chapter 4).
More complex effects can be illustrated with network diagrams.
? The validity of the matrix and the effects identified can be confirmed through consultation with
a regional task force or through interviews with local planning agencies or experts. In project
with major regional significance it may be appropriate to conduct structured public involvement
workshops. The need for local consultation and involvement will be guided by information on
trends and goals (Step 2), the location of notable features (Step 3), and whatever information
is available on project impact causing activities (Step 4).
? GIS, resource capability analysis, and overlay techniques can be combined to produce maps
noting the location of the following elements:
- planned transportation improvements,
- conditions favorable to development,
- constraints to development (physical and regulatory),
- notable features, and
- areas likely to be the focus of changes in accessibility and therefore complementary
development or development shifts.
? The matrix and the mapping exercises should be carefully examined to identify effects meeting
the criteria for significance (magnitude and importance).
Section III: Developing the Scope Page 111-71
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Project Evaluation Context
The methodology for identification of indirect/cumulative effects during the NEPA/SEPA evaluation
of a project would be similar in every respect to the process described for the systems planning
phase. Matrices, network diagrams, inference and consultation techniques, and cartographic
techniques can be combined for a thorough evaluation. The greater detail on project features and
impact causing activities available at this phase allows for greater specification of effects,
particularly encroachment/alteration effects. For more complex projects it may be appropriate to
quantify or weight effects in a matrix so that magnitude can be assessed and comparison of effects
can be conducted. Similarly, more detailed mapping of project features that could produce
encroachment or induced growth effects will reveal areas of susceptibility to change or conflict with
notable features.
Work Product of Step 5
Regardless of the method or combination of methods employed, tabulation is necessary to organize
the information gathered and to make explicit the process used to determine which
indirect/cumulative effects should be carried forward to detailed analysis. Figure III-22 presents a
decision tree outlining the process for evaluating which effects merit detailed analysis and Figure
III-23 provides a table for documenting the evaluation process. The analyst may use the matrix as
a framework for listing potential effects under the major categories provided or others revealed
during earlier scoping tasks. The particular manifestations foreseeable in the study area should then
be documented for each potential effect. In some cases, effects related to induced growth may only
be fully identified after the magnitude and location of induced growth has been estimated (Step 6).
The matrix can then be revisited to ensure that effects in this category are properly identified for
further analysis.
To supplement the tabulation, the analyst should prepare a technical memorandum that describes
the indirect/cumulative effects that warrant further analysis, if any, and presents the scope of detailed
analysis. The technical memorandum should contain relevant documentation supporting the list of
identified indirect/cumulative effects, e.g., checklists, networks, maps, etc., as well as documentation
on those indirect/cumulative effects considered but dismissed from further analysis by agreement
of the involved parties.
Section III: Developing the Scope Page III-72
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Resources and Supplementary Readings
Council on Environmental Quality (1993), Incorporating Biodiversity Considerations into
Environmental Impact Analysis Under the National Environmental Policy Act, Washington,
D.C.
Gramling, Robert and Freudenburg, William R.(1992), "Opportunity-Threat, Development, and
Adaptation: Toward a Comprehensive Framework for Social Impact Assessment," Rural
Sociology, Vol. 57, No. 2.
McHarg, Ian L., Design with Nature (1969), Natural History Press, Washington, D.C.
Rubenstein, H. M. (1987), A Guide to Site and Environmental Planning, John Wiley & Sons, New
York.
Schaenman, Philip S. and Muller, Thomas, Measuring Impacts of Land Development. an Initial
Approach, the Urban Institute, Report No. URI 86000, November 1974.
Section III. Developing the Scope Page III-73
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Figure III-22
Decision Tree for Scoping
Potentially Significant Indirect and Cumulative Effects
Requiring Detailed Analysis
1. Project Purpose and Need
Yes
Explicit economic development purpose?
No,
Proceed to 2
Yes
10
2. Planning Context
Yes
Conflict with local plan?
No,
Proceed to 3
Detailed analysis of
induced growth
effects required
Skip to Step to
determine type
Detailed analysis of
induced growth
effects required
Proceed to 3 to
determine type

3. Project Description - Systems Context
Yes
Planned to serve specific land development? 10
No
Likely to stimulate land development having
complementary functions?
No
Likely to influence intraregional land
development location decisions?
No,
Proceed to 4
Detailed analysis of
this type of induced
growth required
Proceed to 4
Yes
0
4. Environmental Context
Yes
Notable Feature present in impact area? -- Proceed to 5
No
Detailed analysis of encroachment-alteration
effects not required.
End significance evaluation.
5. Project Description - Design Context
Yes Detailed analysis of
Notable Feature significantly impacted? ---? encroachment-
alteration effects
No required
Detailed analysis of encroachment-alteration
effects not required.
End significance evaluation.
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
FIGURE III-23
EVALUATION MATRIX
INDIRECT AND CUMULATIVE EFFECTS REQUIRING DETAILED ANALYSIS
Potential Effect?
Indirect/Cumulative
(Check below.)
Potential Manifestation(s)

Effect Type in Study Area
No Yes (List below or on separate sheet.)
(Assessment (Detailed
Complete) Etmluation
Required)
Encroachment- Ecosystem Related:
Alteration Habitat Fragmentation/Degradation -
Indirect Effects Ecosystem Disruption _ -
Natural Process Disruption _
Single Source Air Quality _ -
Additive Water Quality _ -
(Type 1) and Noise - -
Interactive Other _ -
(Type 2)
Cumulative Socio-economic/Land Use Related:
Effects Community Cohesion/Stability -
Alteration of Travel Patterns _ _
Quality-of-Life Effects - _
Historic Resources _ -
Aesthetic Effects _ -
Other -
Induced Growth Serves Specific Development _ _ Describe magnitude and location;
(Access- evaluate related effects

Alteration Stimulates Complementary Estimate magnitude and location;
Indirect Effects) Development evaluate related effects
Influences Location Decisions Estimate magnitude and location;
evaluate related effects
Indirect Effects Ecosystem Related:
Related to Habitat Fragmentation/Degradation _
Induced Growth Ecosystem Disruption
Natural Process Disruption
Multiple Source Air Quality
Additive Water Quality _
(Type 3) and Noise - -
Interactive (Type Other - -
4) Cumulative
Effects Socio-economic/Land Use Related:
Conflict with Goals/Plans _
Economic/Fiscal Impacts
Community Cohesion/Stability
Alteration of Travel Patterns
Quality-of-Life Effects _
Historic/Cultural Resources
Aesthetic Effects
Other
Project Name:
Location: Analyst: Date:
Section III: Developing the Scope Page III-80
_.. , ., . .
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
SECTION IV
ANALYSIS OF INDIRECT/CUMULATIVE EFFECTS
Section 101(a) of NEPA, "Declaration of National Environmental Policy," reads as follows:
The Congress recognizing the profound impact of man's activity on the interrelations
of all components of the natural environment, particularly the profound influences
of population growth, high density urbanization, industrial expansion, resource
exploitation and new and expanding technological advances... declares that it is the
continuing policy of the Federal Government, in cooperation with State and local
governments, and other concerned public and private organizations .... to foster and
promote the general welfare, to create and maintain conditions under which man and
nature can exist in productive harmony, and fulfill the social, economic and other
requirements of present and future generations of Americans.
This language has two elements pertinent to indirect/cumulative effects analysis: (1) the recognition
of the impact of human activity on the interrelations of all components of the natural environment;
and (2) implication that the impact should be balanced against other considerations. In the scoping
phase, the first of these elements was addressed. Notable features, trends, and goals in the area
surrounding the proposed project were identified and the interrelationship between these features and
the impact-causing activities of the proposed projects and other activities in the area were explored.
The next steps in the framework address the second element of environmental evaluation--the
determination of the probability, magnitude, and location of potential indirect and cumulative
impacts so that the effects of the proposed project may be evaluated in the context of planning,
decision-making, and mitigation considerations.
The analysis of indirect and cumulative effects involves the following steps of the framework:
Step 6 - Analyze Indirect/Cumulative Effects; and
Step 7 - Evaluate Analysis Results
These steps and the methodologies appropriate for carrying them out are described in detail in
Chapters 6 and 7 that follow.
Section IV. Analysis Page IV-I
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
This Page is Intentionally Left Blank.
Section IV: Analysis Page IV-2
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Chapter 6
Step 6 - Analyze Indirect/Cumulative Effects
Overview
Step 5 of the framework illustrated how to identify potentially significant indirect/cumulative effects.
This process of describing the cause/effect relationships between the project and the range of
potential impacts to study area goals and notable features provides the foundation for Step 6, the
analysis of the potential indirect/cumulative effects. The objective of this step is to assess the
significance of the effects identified in the previous step by determining:
? magnitude;
? probability of occurrence;
? timing and duration; and
? degree to which the effect can be controlled or mitigated.
A variety of quantitative and qualitative tools can be employed in the analysis of potential
indirect/cumulative effects. This Chapter will:
? describe the tools available;
? outline steps involved in using the tools for indirect/cumulative effects analysis;
? detail sources for further information regarding each tool; and
? suggest combinations of tools and steps for basic and detailed analysis applications for
systems planning and project evaluation.
Considerations
The first step in the analysis of potentially significant indirect and cumulative effects is to assess the
magnitude, location, and probability of project-induced growth. Step 4 of the framework provided
criteria for assessing a project's propensity for altering the accessibility of an area and Step 5 detailed
the types of project induced growth and the factors contributing to it. If after working through these
steps the analyst determines that project induced growth is unlikely then a detailed analysis is
unnecessary and the evaluation may focus on encroachment-alteration effects.
Once the level of induced growth has been assessed, impacts on the natural environment arising from
the induced development can be evaluated and compared to the impacts of other activities in the
study area. Encroachment-alteration effects arising from the project itself should be assessed after
Section IV: Analysis Page IV-3
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
induced growth impacts are explored so that these alteration effects can be fully understood in the
context of future land uses.
Analyzing induced growth is an exercise in creating and comparing forecasts of future conditions.
At least two forecasts are necessary:
a Base or No-Action Forecast which describes future conditions in the absence of the project
or plan; and
an Action Forecast describing conditions in a future point in time following implementation
of the project alternative or plan.
These forecasts can be designed to fully consider cumulative effects by including significant past and
anticipated actions undertaken by other parties in both the base and project scenarios.
The key in forecasting is an underlying system of logic that can produce reproducible and relatively
consistent results regardless of the forecaster. It should be noted that forecasting is not the exact
determination and prediction of the future, but the logical extrapolation of likely effects that will
occur from known associations among different critical parts of the system.
As with other steps in the framework, induced development forecasting techniques may be either
qualitative or quantitative in nature:
? Qualitative methods can serve to evaluate the context or overall situation wherever little
historical data exist or wherever existing data are questionable or inconsistent.
? Quantitative methods consist of modeling or the search for causal factors, and extrapolation
or emphasis on time series.
Whenever possible, forecasts developed for other purposes by regional planning and transportation
agencies should be utilized. Use of established forecasts as control totals or baselines will not only
reduce the level of effort required in the assessment but will promote acceptance of the findings.
A variety of qualitative and quantitative methods are described below. Examples of how these
techniques can be combined and applied to potential planning and project scenarios are addressed
at the end of this chapter.
Section IV: Analysis Page IV-4
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Methods of Analysis
Forecast tools with applicability to indirect and cumulative effects analysis introduced in Step 5 are
described below in greater detail.
Qualitative Forecast Tools
Literature Review/Comparative Case Analysis
There is a small but growing body of literature concerning the induced development effects of
transportation projects, and other indirect/cumulative effects such as economic benefits to industry
arising from increased access and the economic loss to main street business in bypass projects. This
literature could be useful in developing sketch scenarios for smaller projects. The literature could
also point to instance of comparable cases that merit further study.
A comparative study involves comparing a like area where a similar project has been completed to
the area of concern where a project is proposed. There are several important considerations when
employing this method:
The two projects and areas must be similar in size; project type, location, and design.
Demographic conditions, growth rates and other pertinent characteristics must be
comparable.
? Data sources for the two areas and projects should also be similar.
? Study of the like area essentially consists of beginning with a retrospective analysis (or case
history) in which adequate information regarding conditions in the area prior to the project
would need to be obtained. Although some of this baseline information can be found in
available sources such as an EIS, this information may not match the data requirements. In
other words, the retrospective analysis estimates conditions which no longer exist, a task that
may not be easier than predicting conditions which do not yet exist.
? Retrospective analyses involve separating project-related impacts from those caused by other
factors.
A number of effects that may eventually occur because of the transportation project may not
have yet occurred, e.g., because of an economic downturn.
Comparative case analysis entails a double effort for data collection and assumes that the proposed
project has an accessible twin. Even if similar circumstances can be found, the results may differ
because of various random and non-random effects. Objectives and policies, for example, tend to
change over time. While it would be preferable to compare the proposed project with several
Section IV: Analysis Page IV-5
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
analogous cases, this would entail more resources. It is obvious that caution must be used in
implementing comparative case analysis. However, comparative case does have potential for
improved identification of indirect/cumulative effects that are otherwise difficult to identify.
Scenario Writing
Scenarios are an outline in narrative form of some conceivable future environment given certain
assumptions about the present and a sequence of events in the intervening period. Multiple scenarios
can be drafted to include a variety of changing conditions, a spectrum of potential developments, and
a series of hypothetical socio-political, ecological, and economic consequences of proposed actions.
Rather than predictive, scenario writing is a technique which attempts to establish some logical
sequence of events to show how, under present conditions and assumptions, a future environment
might evolve. Scenarios can also serve to set the upper and lower bounds of potential outcomes.
A particular difficulty in scenario writing is consideration of the various uncertainties in forecasting
arising from long-range, future-oriented planning. Included are broader uncertainties about the
external planning environment; future intentions of other decision makers; appropriate value
judgements; and institutional and social changes. Another difficulty is in uncovering a variety of
variables that may not be apparent in the present but which may be of significance in future
environments.
There are obvious questions regarding the extent of completeness, validity, or overall accuracy or
reliability of scenarios. Effective scenario writing requires continuous questioning of the values,
insights, assumptions, and level of information of the scenario writer(s). The level of confidence in
scenario writing, therefore, depends on both the plausibility and credibility of the argument, and on
the competence and qualifications of the scenario writer(s).
Delphi Technique/Expert Panel Survey/Public Involvement
Thorough surveys of local experts, stakeholders, and professionals can be invaluable in developing
assumptions and assessing future conditions. Survey techniques can include informal conversations;
formal inquiry following an instrument administered by mail, phone, or interview; or discussions or
meetings of a collaborative task force or panel (a sample survey instrument is provided in Appendix
A). The most structured consultation method is the Delphi technique. Delphi is a survey research
technique directed toward the systematic solicitation and organization of expert intuitive thinking
from a group of knowledgeable people (Linstone, 1975). It provides a means for arriving at an
informed, objective judgement based upon a variety of sometimes conflicting opinions. Rather than
achieving consensus by open discussion, Delphi uses a carefully designed program of sequential
individual interrogations interspersed with information and opinion feedback derived from
consensuses which are computed from earlier parts of the technique.
Section IV: Analysis Page IV-6
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Figure N-1 shows the logical sequence of a typical Delphi study and its series of questionnaire
rounds. The issues must be structured carefully to bring out the most important questions. This
technique provides sensitivity for potential futures and opinions for delineating probable future
actions. It can be used to obtain expert opinion on cause and effect relationships and related
probabilities when adequate models are not available. Skilled facilitation is required to elicit the
experts' opinions. Selection of experts and methods to avoid means of influencing opinion are other
important elements of Delphi.
While this technique is less well-defined and requires more expert direction than other detailed
qualitative techniques, it can develop ideas and identify causal relationships that might not surface
in more structured methods. There are several examples of the technique's application to practice.
Recently the Texas Department of Transportation has used the Delphi method to allocate population
and employment control totals to Traffic Analysis Zones, in order to evaluate the potential
development effects of transportation improvements (Gamble, 1993).
Expert panels or detailed interviews with local real estate, government, and industry leaders may be
a workable substitute for the Delphi method when panelists would be unable to participate in an
iterative process. Less formal methods, lack the feedback and review features of Delphi but may be
used to construct or confirm assumptions employed in other qualitative or quantitative techniques.
Project task forces made up of a representative mix of community stakeholders can also help define
and refine forecasts techniques and results especially when coupled with public outreach meetings
or charettes designed to gauge the range of community expectations regarding project induced
growth. Task force and outreach techniques can also serve to build consensus that would promote
broad acceptance of findings.
Section IV: Analysis Page IV-7
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Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Quantitative Forecast Tools
Trend Extrapolation
Trend extrapolation is a commonly used method of projection, based on the analysis of time series
data. The technique requires holding the assumption that the factors which contributed to the trend
in the past are more likely to remain constant than to change in the time period of future
consideration. Future baseline estimates of population, employment, housing starts, and other
conditions can be predicted using this method. There are a number of trend extrapolation techniques
including:
? Simple (straight line) extrapolation - finding a line which best fits a plot of time series data and
using the linear equation for that line to project data points in future periods.
Curve fitting (polynomial, exponential) - finding a curve which best fits a plot of time series
data and using the equation for that exponential relationship to project data points in future
periods.
? Asymptotic (upper limit) curves - finding a curve which best fits a plot of time series data with
an upper limit on data values; the limit function equation allows for projection of the curve into
the future as it approaches an upper limit.
Choice of an extrapolation technique requires judgement based on the data and the situation. For
example, exponential curve fitting is best applied to areas growing at a rapid rate. Envelope or
asymptotic curves should be employed when known limits on scarce resources such as available
land, or sewer and water infrastructure, would inhibit future growth. See Figure IV-2 for examples..
Once the data has been gathered, trend extrapolation projections can be prepared with little effort
using standard automated functions of spreadsheets (e.g., Excel, QuatroPro), statistical packages (e.g.
SPSS, SAS), or other data processing software.
Trend extrapolation techniques are limited in their application to indirect/cumulative effects analysis,
because the techniques are only useful in creating base case or no-action forecasts-extrapolation is
not helpful in evaluating project alternatives that will by definition change conditions on which
historical trends are based. Also, this type of forecasting technique is unnecessary when accepted
forecasts have been developed already by local or regional agencies for the study area.
Section IV: Analysis Page IV-9
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
Trend extrapolation techniques have been criticized for being too simplistic. Other drawbacks
include:
? Projections taken out too far into the future (more than 5 years) or based on too few historical
data points may be seriously flawed.
? The assumption that conditions supporting past trends are unlikely to change is often unrealistic
in an age when technology and public opinion can undergo rapid shifts.
Despite these drawbacks, trend extrapolation can serve indirect/cumulative effects analysis best
when, after the trend has been projected, there is detailed exploration of factors supporting
continuation of the trend and factors or developments that will alter, limit, or violate the projected
trend.
Section IV. Analysis Page IV-10
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Figure IV-2
Examples of Trend Extrapolation
Population of Mecklenburg County,
(Charlotte) 1900-2000
1,200,000
1,100,000
1,000,000
to 900,000
y 800,000
a 700,000 2
0 600,000
500,000
E 400,000
z 000
300
,
200,000
100,000
0
1900 1920 1940 1960 1980 2000 2020 2040
Year
Linear Equation: The linear equation is not the best fitting curve in circumstances where
growth becomes exponential.
1,200,000
1,100,000
1,000,000
900,000
U)
O 800,000
N
a 700,000
0 600,000
500,000
3 400,000
z
300,000
200,000
100,000
0
Population of Mecklenburg County,
(Charlotte) 1900-2000
1900 1920 1940 1960 1980 2000 2020 2040
Year
Curvilinear Equation: A polynomial equation provides the curve with the best fit to the
data but projection of the high rate of growth in the past to the future may not be realistic.
Linear Equation:
- y = 6506.7x - 1 E+07
-- R = 0.9232 -- --
•
•
Section IV: Analysis Page IV-11
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Figure IV-2 (cont'd)
Examples of Trend Extrapolation
1,200,000
1,100,000
1,000,000
900,000
N
0 800,000
N
700,000
ti c 600,000
L
500,000
400,000
Z
300,000
200,000
100,000
0
Population of Mecklenburg County,
(Charlotte) 1900-2000
Asymptotic Curve:
growth with a limit function of
900,000 persons
1900 1920 1940 1960 1980 2000 2020 2040
Year
Asymptotic Curve: Using a limit function to constrain growth to an upper limit may
be more consistent with reality but the accuracy of the projection will be entirely
dependent on the accuracy of the limit that has been set. The constraint, therefore
should be based on a factor that would reasonably be expected to curtail growth, such
as the carrying capacity of the land, or limits of the water supply.
Section IV. Analysis Page IV-12
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
Build-Out/Carrying-Capacity Analysis
In a quantitative forecast exercise for indirect/cumulative effects, it is necessary to relate projections
of population and employment with consumption of land. Unless this step is integrated into the
formal land use model, the analyst must determine standards for land consumption by land use.
(Population can be related to land use by determining the number of units per acre and the average
household size; similarly, employment can be related to land use by utilizing standards of employees
per square foot or per acre for various types of commercial development; see Figure IV-3 for
example standards). The goal is to compare how land consumption will differ with and without the
proposed transportation improvement.
In areas with established land use controls, the analyst can:
? develop a no-build scenario by analyzing current regulation and anticipated plans, keeping in
mind historical trends in the granting of variances or passage of changes to the zoning
ordinance;
? determine the carrying capacity foreach zone given development regulations and environmental
constraints and determine when build-out is likely to be achieved;
? determine if the timing of development is likely to be influenced by the build-alternatives using
other quantitative or qualitative techniques described here; or
? determine if the build alternatives are likely conflict with land use regulations or create
development pressures that may result in revision of land use regulations assumed in the no-
action scenario.
In areas where land use is not widely controlled or where population projections have not been
related to land consumption, it may be necessary to develop a no-action future scenario from scratch
utilizing assumptions about location choices and land consumption with and without the
transportation improvement. These scenarios can be developed using any of the other quantitative
or qualitative techniques described below.
Section IV: Analysis Page IV-13
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
FIGURE IV-3
Typical Values for Land Consumption by Land Use Type
Residential Land Uses
Where available, densities permitted in applicable zoning or development regulations should be
used. The table below illustrates typical values.
Housing Type Units (Households) Per Acre
Rural Single Family Dwelling (SFD) 0.25
Low Density SFD 1.00
Conventional SFD 3.00
Small Lot SFD 5.00
Townhouse 10.00
Garden Apartment 15.00
Mid-Rise Apartment Building 15.00
High-Rise Apartment Building 60.00
Mixed-Use Building 12.00
Non Residential Land Uses
Where available, Floor Area Ratio (FAR) permitted in development regulations should be used in
place of typical numbers used below.

Structure Type Square
Feet per
Employee Average
Building Size
FAR Average
Lot Size Average Number
of Employees/Acre
Office 333 25,000 0.40 1.43 52.32
Retail 400 10,000 0.20 1.15 21.78
Warehousing/Distribution 667 10,000 0.25 0.92 16.33
Transportation
Streets can be assumed to account for 17 percent of gross land area for all land use types.
Source: Social Cost of Alternative Land Development Scenarios (SCALDS) model, FHWA, 1998.
Section IV: Analysis Page IV-14
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Regression Analysis/Econometric Forecasting Techniques
Trend extrapolation techniques are used to determine how one dependent variable (such as
population, household size, or number of building permits issued) has varied with a single
independent variable (time) in the past, so that a prediction may be made about the future.
Regression and econometric techniques allow a forecaster to explore the relationship between a
dependent variable and several independent variables, either in time-series or cross-section to predict
future events. Although many forms of regression analysis may be employed in forecasting, as an
example, we will discuss Ordinary Least Squares regression.
The first step in regression analysis is to establish a hypothesis regarding the relationship of an
dependent variable such as population to the various independent variables for which data is
available at the proper level of aggregation. This hypothesis takes the form of a linear equation. For
example, to forecast population growth one could hypothesize that population in a zone is a function
of accessibility to employment centers in other zones, land zoned for residential use, housing costs,
availability of water and sewer service, and crime rates. The linear equation matching this theoretical
model would be:
Pj = loo + A(Aj) + A(Li) + A(Hj) + A(W) + A(Q + e
Where:
Pj = Population in zone j
Aj = Average travel time to major employment centers
Lj = Acres zone for residential use
Hj = Average unit purchase cost for housing
Wj = Presence of water/sewer service
C. = Crime rate per thousand persons
A = Constant (intercept)
A= Coefficient (slope)
e = Error term
Undertaking a regression analysis and evaluating the statistics produced for an equation like the one
above allows the analyst to:
? determine how well the independent variables explain the variation in the dependent variable
(R2 statistic explains the proportion of variability explained by the model);
? obtain an indication of relative importance of each variable in the model (t-statistics indicate
the strength of the contribution and can be used to determine whether the contribution is
significant-insignificant variables should be dropped from the model); and
? predict the independent variable for any given value of the dependent variables (through
application of the coefficients in the equation).
Section IV: Analysis Page IV-I5
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Good data and a well-formed model could be used to predict changes in population or employment
in an area based on changes in an accessibility arising from an project alternative. This would be
achieved by varying the accessibility component of the equation while holding other variables
constant. Regression analysis could also be used to determine the relative weights of variables
determining location attractiveness to be used in a gravity model equation (see below).
Simple Gravity Model
Gravity models follow from the observation that the attractiveness of a location as destination for
travel is a function of its "mass" (measured in square footage, for example), and the distance to other
similar regional destinations. As in the formula for gravitational attraction used in physics, distance,
the denominator, is squared or raised to the power of another exponent to represent its greater
importance when compared to mass.
This formulation of mass over distance can also be adapted to predict the location of future
concentrations of households or employers as regional accessibility changes. This method allocates
predetermined growth in employment and population for a study area to subareas based on mass (the
presence of attractors such as population, employment, vacant land, and other factors) and friction
(distance between attractors in travel time). Control totals used for allocation can be developed
using other forecasting techniques or preferably the totals can be based accepted forecasts developed
by state or regional planning agencies.
The process described below is a very simplified version of some of the more sophisticated
integrated land use and transportation models. In this formulation the allocation of employment is
conducted first and then population is allocated based on employment location. The results derived
can be expected to be less accurate than output from formal, calibrated models, but can be used to
indicate trends and supplement qualitative analysis based on interviews with local experts. Steps
involved in one version of the gravity model are described below.'
Step 1: Allocate Employment Control Totals to Zones
Step IA: Determine index of accessibility for each zone
The accessibility index (Aj) for a zone j is calculated as:
Aj = EP; / Dii" i # j
'Adapted from Donald Krueckeburg and Arthur Silvers, Urban Planning Analysis: Methods and Models,
New York: John Wiley & Sons, 1974.
Section IV: Analysis Page IV-16
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Where:
P; = Population in each other zone i
D;j = Time distance from zone j to each other zone i (from travel model)
X = exponent related to friction factor (2, or derived from observation)
Step 1B: Determine employment growth in each zone
Employment growth in each zone (Gj) is calculated as:
Gj = G,(LjAj / E L;A;)
Where:
Gt = Growth in employment in entire study area (determined exogenously)
Lj = Land (space) available in zone j
L; = Land (space) available in each zone i
Step 1C: Add employment growth to employment totals and subtract some measure of available
land utilized (either estimated or observed) by this growth from Li.
Step 2: Allocate Population Control Totals to Zones
Step 2A: Determine index of accessibility for each zone
The accessibility index (Aj) for a zone j is calculated as:
Aj = EE; / Djj1 i # j
Where:
E; = Employment in each other zone i (new totals from Step 1)
Step 2B: Determine population growth in each zone
Population growth is calculated by using the same formula described in Step 1B, substituting
estimated growth in population for the study area (G,), and the new measure of accessibility to
employment (A).
Step 2C: Add population growth to population totals and subtract some measure of available
land utilized (either estimated or observed) by this growth from Li.
The steps could be repeated for five-year intervals or for any other period where the exogenous
predictions of overall growth in employment and population are available.
Section IV: Analysis Page IV-17
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Other factors that contribute to the attractiveness of a location to employment or population could
be added to the equation. These factors include land value, availability of infrastructure such as
water and sewer, and quality of life measures such as housing condition and crime. When adding
other factors to the model, care should be taken to establish the relationships between the variables
by assigning weights. Weighting can be achieved by using a regression model to determine the
importance and significance of factors or by surveying stakeholders or local experts.
Policy considerations could be accounted for by modifying the available land variable (L) to take
into account zoning, use, density, and conservation area restrictions. Calculating this variable would
involve decisions or assumptions about environmental and physical constraints (wetlands, slope,
brownfields) and may require use of GIS analysis to cull and sum up vacant parcels or portions of
parcels in each zone.
Economic and Fiscal Impact Modeling/Cost-Benefit Analysis
The construction and operation of transportation facilities often result in direct economic and fiscal
impacts. These direct impacts include the temporary increase in employment attributable to
construction, the increase in business to local suppliers as construction materials are purchased, the
increase in productivity as travel costs are reduced, and the loss of local property taxes resulting from
the acquisition of right-of-way. There are other, indirect economic and fiscal impacts, however, that
may be accounted for in the assessment of proposed transportation improvements. Examples of
indirect impacts include:
? The multiplier effect generated as direct expenditures on construction and maintenance materials
increase demand for raw materials and intermediate products throughout the local and regional
industry supply chain.
? The multiplier effect generated as local construction and maintenance employees spend wages
on consumer goods.
? The direct and indirect impacts of the decline in economic activity as traditional business areas
are bypassed by a new transportation facility.
? The direct and indirect impacts of an increase in economic activity as new business are
developed to serve the increase in traffic attributable to a transportation improvement.
? The direct and indirect impacts of an increase in tourist activity resulting from gains in
accessibility attributable to the transportation improvement.
? The direct and indirect impacts of an increase in economic activity as other businesses are
attracted to the area by gains in accessibility and productivity attributable to the transportation
improvement.
Section IV. Analysis Page IV-18
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
? The fiscal benefits (increase in property taxes) resulting from a rise in property values
attributable to project induced growth.
? The adverse fiscal impacts (increase government spending) resulting from the greater need for
services (infrastructure, schooling, public safety) attributable to project induced growth.
Although it is generally possible under most circumstances to estimate the construction and
maintenance impacts described above, it is often more difficult to quantify the economic/fiscal
benefits and costs of project induced growth or increased accessibility. To the extent that project
induced growth is quantified using other techniques in described in this chapter, however, it would
be possible to use a common set of economic and fiscal impact tools to estimate these types of
potential effects.
Because the direct and indirect economic impacts attributable to proposed transportation
improvements are closely intertwined it will often be useful to analyze them simultaneously. There
are four broad categories of direct and indirect impact measures to consider when evaluating project
alternatives in a cost-benefit framework (TRB Circular 477, 1997):
1) User Impacts (value of each of the following measures may be combined to measure total
impact)
- money cost of travel
- travel time
- safety
- comfort, reliability, etc.
User impacts are most often direct in nature, so they will not be covered in detail here. User
impacts are best measured through transportation demand models.
2) Economic Impacts (each of the following measures is an alternative way to express total
impacts, the measures are not additive)
- employment
- personal income
- business sales volume
- property values
- value added
- business profit
Economic impacts can be direct and indirect in nature. Direct impacts are attributable to
spending on construction and maintenance itself. Indirect and induced impacts are attributable
to project induced growth and the multiplier effects arising from direct spending.
Section IV: Analysis Page IV-19
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Basic methods to measure direct and indirect economic impacts include:
Input/Output Models - These models rely on accounting tables (produced and updated on a five-
year basis in the United States by the Bureau of Economic Analysis) that describe the linkages
of inter-industry purchases and sales. With certain modifications, the data can be tailored to
provide information applicable to a specific region. The models yield multipliers that show the
full effect on all industries as final demand for the products produced by a proscribed set of
industries (those involved in highway construction, for example) is increased or decreased. The
multipliers allow for calculation of the direct, indirect, and induced output (sales), earnings
(wages), and employment (full-time equivalent jobs) impacts. Models are commercially
available from the Minnesota-based IMPLAN Group, the Regional Science Research Institute
(PC I/O Model), the U.S. Bureau of Economic Analysis (RIMS-II) and many transportation
planning consulting firms.
Macroeconomic Simulation Models - These models include the function of I/O models
described above and additional features used to forecast the effects of future changes in business
costs, prices, wages, taxes, productivity and other aspects of business competitiveness and shifts
in population, employment, and housing value. As with I/O models, these methods can be used
to evaluate the consequences of factors beyond travel costs impacts such as project induced
growth, if the growth impacts are quantified with techniques exogenous to the model.
Simulation models are available for rental, purchase, or custom studies. Examples include
REMI (Regional Economic Models Inc.) and DRI-McGraw Hill.
Business Market and Tourism Attraction Studies - Specific factors unique to the study area can
contribute to the attraction of businesses and tourists. Business factors such as proximity to
suppliers, markets, and other modes of transportation, and tourist factors such as proximity to
unique existing or proposed recreation, historical, or commercial amenities must be studied in
detail to assess the potential for attraction that may improve with the accessibility attributable
to the proposed transportation improvement.
3) Government Fiscal Impacts (value of each of the following measures may be combined to
measure total impact)
- public revenues
- public expenditures
Fiscal impacts arising from induced growth and land use changes attributable to transportation
improvements can be calculated by using the analysis method described in this chapter for
assessing induced growth combined with standard fiscal impact methodologies. Once the range
of potential growth outcomes has been quantified, service standards describing the cost of
providing additional infrastructure, education, emergency services, and other government
functions can be applied to determine costs. The calculation of benefits must rely on
assumptions based on the current profile of property taxes and ratables.
Section IV: Analysis Page IV-20
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
The recently developed SCALDS model (Social Cost of Alternative Land Development
Scenarios) available through FHWA provides a framework for applying the fiscal costs and
benefits related to transportation improvements. The model is described in more detail under
Integrated Transportation and Land Use Models below.
4) Other Societal Impacts (value of each of the following measures may be combined to measure
total impact)
- air quality
- impact to environmental features
- change in societal conditions
Air quality impacts studies are most often limited to the direct impacts attributable to the
proposed transportation improvement. The SCALDS model (described in more detail in Volume
I, Appendix A) provides a framework for assessing air quality impacts related to induced
development. Impacts to other features can be estimated using the other techniques described
in each step of the indirect/cumulative effects analysis framework.
Integrated Land Use and Transportation Models
Transportation planners have long relied upon computer based models to predict how traffic patterns
change with improvements to the transportation system. In the last two decades, there have been an
increasing number of models that also predict the indirect land use effects of transportation
projects-land development and the location of households and employers. To properly simulate
the relationship between land use and transportation, integrated models are required. These models
predict how changes in accessibility influence changes in location and how the congestion created
by relocated households and businesses, in turn, affects accessibility. Several approaches have been
employed to simulate locational decisions but it is the feedback between the transportation and land
use components of these models that make them integrated and useful in the analysis of
indirect/cumulative effects.
Since the early 1990s, computer modeling of land use patterns has become more sophisticated. In
recent years, developers have undertaken improvements in the feedback loop between travel demand
and land use components, have improved the process of calibration, and have added Geographic
Information System software as a graphical interface for data input and output. Even the more
complex computerized models now run quickly on standard desktop computers. This increased
sophistication and improved usability has contributed to wider use of models at state agencies and
MPOs.
A 1995 study described the results of a survey of model use at MPOs in the thirty-five largest
metropolitan areas. Eighteen of the thirty-five employed or were planning to employ modeling
techniques at the time of the survey: twelve indicated that they use one particular model (DRAM-
Section IV: Analysis Page IV-21
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
EMPAL); another six have developed or are developing their own models. The remaining MPOs
employed qualitative techniques including the Delphi method to allocate forecasted population and
employment. (Porter, 1995)
Land use and transportation models that are currently available for implementation are examined in
detail in Volume I, Appendix A. In metropolitan areas where a state agency or MPO utilizes land
use and transportation modeling techniques the analyst may wish to explore the possibility of
utilizing the model to evaluate alternative future transportation and development scenarios.
Section IV: Analysis Page IV-22
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Application of Analysis Techniques
The analysis techniques described above are applicable to a wide variety of systems planning and
project evaluation circumstances. This section provides examples of how the methods discussed in
this handbook can be combined to produce a complete analysis of indirect/cumulative effects.
Examples are provided for analysis in the context of transportation systems planning and project
evaluation under NEPA/SEPA.
There are several considerations involved in choosing appropriate analysis techniques to match
project types and study area conditions. Figure IV-4 outlines factors related to the size, location, and
characteristics of a project that could influence the level of effort and methodology.
There are three general steps necessary to analyze indirect/cumulative effects:
Assessment of the magnitude and location of development induced by a project should be
the first step taken in the analysis, so that other effects may be analyzed in context..
The forecasts developed should include other activities in the study area that could impact
notable features. Cumulative and indirect effects can be evaluated by comparing the Action
and No-Action forecasts.
? Encroachment alteration effects attributable to the project and the induced development may
then also be evaluated in the context of the Action and No-Action forecasts.
Considerations important to carrying out each of these analysis steps are discussed below.
Section IV: Analysis Page IV-23
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Analyzing Induced Development
As discussed in Chapter 5, there are three types of induced development that must be considered.
Application of analysis techniques to each of the three types of effects is discussed below.
Specific Development Proposals
Where transportation projects are designed to serve specific development proposals or economic
development goals, the details of those projects or plans should be ascertained and documented as
thoroughly as possible.
? Planned or estimated levels of new housing units, and commercial/industrial space can be
used to develop estimates of population and employment using the standard factors outlined
in Figure N-3. These factors may also be employed when only the acreage of proposed land
uses are known.
? The size and location of the development site and its individual elements should be
documented where known so that conflicts with notable features may be evaluated.
? Where the impacts described above have been documented as part of studies commissioned
to evaluate the development proposal, the findings should be referenced, so that conflicts
with notable features and community goals may be described.
? Large development projects (especially those dedicated to a single office or residential use)
may induce their own demand for development activity (residential, retail, and service
activity to meet the demands of residents or employees of the new complex). Economic
impact modeling, comparative case, or literature techniques may be employed to estimate the
magnitude and location of this induced development.
Complementary Development
Factors contributing to the development of complementary land uses in the vicinity of proposed
transportation projects (e.g., traffic volumes, distances to regional centers) and common patterns of
that those uses take are outlined in Chapter 5. Once it has been determined that these elements are
present at select interchange, intersection, or station locations, the likelihood and magnitude of the
complementary development should be evaluated through the application of one or more of the
following techniques.
Literature Review/Quantitative Analysis - Studies regarding commercial development at
rural highway interchanges (see Hartgen & Kim, 1998; Hartgen, 1991) suggest minimum
thresholds for traffic on connecting roads that would support various types of complementary
development (See Figure IV-5). Estimates for average daily traffic (ADT) on intersecting
Section IV: Analysis Page IV-25
Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
roads developed during the analysis of project purpose and need or derived from traffic
counts or a travel demand model could be compared to these thresholds to determine the
likely profile of complementary development at an interchange location under Action and
No-Action conditions.
Comparative Case Analysis - An analyst could review development patterns at interchanges
for projects and study areas with similar characteristics to determine the likely general
profile for development patterns at interchange or station locations.
Scenario Writing - An analyst, using general data from the literature, comparative cases, or
expert panel input could write scenarios representing the likely upper and lower bounds of
complementary development at interchange or station locations under Action and No-Action
conditions. Locations could be ranked based upon the criteria noted in Chapter 5 to evaluate
whether a particular location would be likely to correspond to the higher or lower
development scenario.
Once the nature of complementary development at various locations has been estimated the
development scenarios can be evaluated for conflicts with notable features and community goals (see
discussion of encroachment alteration effects below).
Intra-Regional Development Shifts
Analysis of intra-regional development shifts may be appropriate in the transportation systems
planning context and the project evaluation context. Examples of technique application are outlined
below.
Transportation Systems Planning - TEA-21 implicitly recognizes the importance of considering
indirect and cumulative effects in the planning of transportation systems that takes place before the
NEPA process. By considering the range of potential indirect and cumulative effects in the
evaluation of mode and corridor alternatives the sponsoring agency can better evaluate the broad
range of alternatives and lay the ground work for indirect and cumulative effects analysis required
by NEPA/SEPA in the evaluation of project alignment and design alternatives.
The assessment of indirect/cumulative effects in the planning phase involves the following
considerations:
Section IV: Analysis Page IV-26
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
FIGURE IV-5
CRITERIA FOR DEVELOPMENT SUITABILITY
AT RURAL INTERCHANGES
Motels:
Would have good prospects for development if the interchange:
Is less than 1 mile from public water and sewer service.
Has crossing road traffic volumes of 4,000 vehicles per day or more.
Is less than 20 miles from the nearest intersecting Interstate Highway.
Gas Stations:
Would have good prospects for development if the interchange:
Is less than 1 mile from public water and sewer service.
Has crossing road traffic volumes of 10,000 vehicles per day or more.
Is less than 1 mile from the nearest town.
Fair prospects if the interchange:
Has crossing road traffic volumes of 5,000 vehicles per day or more.
Is less than 3 miles from the nearest town.
Fast-Food Restaurants:
Would have good prospects for development if the interchange:
Is less than 1 mile from public water and sewer service.
Has crossing road traffic volumes of 7,000 vehicles per day or more.
Is less than 20 miles from the nearest intersecting Interstate Highway. Fair prospects if the interchange:
Has crossing road traffic volumes of 5,000 vehicles per day or more. Is less than 3 miles from the nearest town.
Sit-Down Restaurants:
Would have good prospects for development if the interchange:
Is less than 1 mile from public water and sewer service.
Has crossing road traffic volumes of 10,000 vehicles per day or more.
Is less than 5 miles from the nearest intersecting Interstate Highway.
Residential Development:
Would have good prospects for development if the interchange:
Has crossing road traffic volumes of less than 10,000 vehicles per day.
Is less than 1 mile from the nearest town.
Fair prospects if the interchange:
Has crossing road traffic volumes of less than 20,000 vehicles per day.
Is less than 3 miles from the nearest town.
Low-density residential development in the vicinity of an interchange tends to become more likely if an interchange
is near a town, and if there is less likelihood of commercial development. In other words, if conditions are suitable
for commercial development, residential development is generally less likely to occur. Therefore, those interchanges
which are the least suitable for commercial development are more suitable for residential, provided that there is a
nearby town.
Source: Hartgen, et al., 1991
Section IV: Analysis Page IV-27
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
? Induced Growth - Because details related to alternative selection and design are usually
unknown in the planning phase, the focus of the assessment is on the potential for induced
growth and related social and ecological effects. Where plans regarding access nodes (e.g.,
interchanges, stations) are known, consideration can be given to localized induced growth
effects and encroachment-alteration effects on notable features.
? Link between Land Use Futures and Transportation - In the planning of transportation
systems, future demand for travel is an important consideration. This demand is related, in
part, to anticipated growth in population or employment and land use decisions made by
those groups. Although these variables are part of Travel Demand Modeling efforts used
throughout many urbanized areas to evaluate plan alternatives, there must be specific
feedback between transportation and land use systems to adequately evaluate
indirect/cumulative effects. Very often a land use scenario is used to determine travel
demand but the impact of a transportation system on land use decisions is not explored. This
feedback loop is at the heart of induced growth analysis. Feedback is achieved by developing
qualitative or quantitative land use scenarios based on the change in accessibility attributable
to each planned alternative. Cumulative effects are addressed by incorporating other actions
into the transportation and land use scenarios.
? Link between Land Use Futures and the Environment - The final step in a complete indirect
and cumulative effects evaluation at the planning stage is the linking of land use forecasts
to notable features in the physical and natural environment. This is most easily accomplished
using a cartographic overlay technique or GIS. These methods would allow for graphical
representation of potential areas of conflict between the transportation system, anticipated
planned and induced development and notable features in the environment in both the
planned corridor and surrounding area. In determining the location of future growth and the
potential for conflict with land use plans it is important to note a community's intention to
adhere to a plan and its past history of granting rezoning and variance approvals that could
alter land use plans.
? Revising and Updating Analyses - Indirect and cumulative effects analyses conducted during
the planning stage may serve as a good base for the analyses to be conducted in the
evaluation of alignment and design impacts. Since significant periods of time often elapse
from the evaluation of system plans to the environmental documentation for plan
alternatives, however, care should be taken to re-evaluate assumptions in light of the time
elapsed and greater knowledge of project details. Encroachment-alteration effects should
also be explored as greater detail on project design is revealed. Sensitivity and risk analysis
techniques (see Chapter 7) can be valuable tools in exploring the extent to which findings
in a forecast change as assumptions change. Survey or expert panel techniques or a rerun of
a forecast model could provide update to assumptions that may be required.
Section IV: Analysis Page IV-28
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The methods described in this chapter can be combined in various ways to analyze
indirect/cumulative effects in the planning phase. Options in methodology include but are not
limited to the following examples.
Example 1:
? Use survey of experts, consultation with local planners, or local/county comprehensive plans
to develop base forecast of population, employment, and land uses for groupings of TAZs
or other subregional level of analysis.
? Use survey or panel consultation techniques to develop criteria for reallocation of
population/employment/land uses to subregional areas in the vicinity of a transportation
corridor to be improved. Reallocation should be considered for each plan alternative.
? Map base and action alternative forecasts along with key environmental features drawn from
existing secondary sources to reveal areas of potential social or ecological impact.
? Using findings from mapping exercise, consultation techniques, and literature/comparative
case review to write scenarios for base and alternative forecasts. Compare scenarios to each
other and significance criteria to draw general conclusions about impacts.
Example 2:
? Use a gravity model to allocate study area population and employment control totals to
groupings of TAZs based on calculation of land available for development in each group and
accessibility to other groups in the study area. Accessibility is calculated from zone-to-zone
travel times produced by a Travel Demand Model (TDM) aggregated to the TAZ group level.
? Repeat the gravity model exercise for each plan alternative with new accessibility factors
derived from runs of the Travel Demand Model including the mode or corridor alternative.
? Map base and action alternative forecasts derived from gravity model runs along with key
environmental features drawn from existing secondary sources to reveal areas of potential
social or ecological impact.
? Using findings from mapping exercise, and supplementary consultation techniques, and
literature/comparative case review to write scenarios for base and alternative forecasts.
Compare scenarios to each other and significance criteria to draw general conclusions about
impacts.
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Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
Example 3:
Employ an integrated Transportation-Land Use Model that uses TDM files for travel time
input. The model will be run several times to examine each possible combination of
transportation and policy alternatives. The model will be based on exogenously determined
control totals and will be calibrated based on historical data and the professional judgement
of agency analysts and local experts.
Model output can be mapped using standard cartographic or GIS techniques along with key
environmental features drawn from existing secondary sources to reveal areas of potential
social or ecological impact.
Using findings from mapping exercise, and supplementary consultation techniques, and
literature/comparative case review to write scenarios for base and alternative forecasts.
Compare scenarios to each other and significance criteria to draw general conclusions about
impacts.
Project Evaluation - The methods employed in the analysis of project alternatives for NEPA are
similar to those employed in the planning phase. Since project characteristics and circumstances are
more refined however, the techniques, particularly the quantitative methods can be employed at a
greater level of detail. Examples of how techniques can be combined to conduct analyses are given
below for two possible scenarios-a scenario requiring basic techniques and one requiring a more
detailed analysis. Tools should be tailored for the particular project circumstances, and level of
information and resources available.
Example 1 - Basic Analysis Techniques:
The addition of an interchange to a limited access highway in a low-growth rural location is expected
to have minimal potential for induced growth. To assess the induced growth potential and predict
its magnitude the analyst would:
Use simple trend extrapolation techniques to produce baseline study area projections of
population and employment for the 20-year assessment period. (This was necessary because
the county planning office had not conducted forecasts for the area.) Analyst writes uses data
to develop a "No Action Scenario" describing future conditions without the improvement.
Cite literature showing that interchanges in rural areas far removed from the urban core or
employment centers are likely to induce only limited highway oriented development like
service stations and convenience stores in quadrants nearest to oncoming traffic.
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? Cite the limited nature of development following a similar project in an adjacent county 10
years ago.
? Write a scenario describing potential impacts from the conversion of a vacant parcel and
several acres of nearby farmland to use by two gas stations, a convenience store, and a
restaurant attracted to serve traffic using the new interchange. Analyst concludes that this
scenario describes the lower boundary of reasonably foreseeable induced growth.
Write a scenario describing impacts arising from the construction of a large truck stop, a
hotel, and several fast food restaurants. This scenario details the highest magnitude of growth
that is reasonably foreseeable given assumptions established by the analyst.
Example 2 - Detailed Analysis Techniques:
A beltway in high-growth rural and suburban fringe location is anticipated to create opportunities
for commercial and residential development involving the conversion of agricultural and forest land.
To gauge the impact that the new facility will have on the pace and location of development in the
study area the analyst would:
Develop a general No Action Scenario for the study area based on 20-year growth projections
furnished by the local Metropolitan Planning Organization (MPO).
? Use a gravity model to allocate study area population and employment control totals to TAZs
based on calculation of land available for development in each zone and accessibility to other
zones. Accessibility is calculated from zone-to-zone travel times produced by a Travel
Demand Model (TDM) used previously by the MPO. At the end of the process the No
Action Scenario is refined to describe future development on the TAZ level.
? Repeat the gravity model analysis for every project alternative based on changes in zone-to-
zone travel time produced by a TDM analysis of project alternatives conducted by the MPO
previously to evaluate project feasibility.
Calculate land consumed in each TAZ by population and employment growth and maps the
findings on the GIS maps created to show existing conditions. This analysis reveals potential
areas of conflict with the natural environment (induced-growth related impacts) and current
land use regulations.
Compare gravity model findings with surveys of local real estate development and land use
professionals and other stakeholders.
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? Develop a scenario for project alternatives based on findings from quantitative and
qualitative analyses.
Analysis of Encroachment Alteration Effects
Encroachment-alteration effects can be classified into three basic categories:
? Effects related to characteristics of the proposed project (see Chapter 4 for characteristics;
Chapter 5 for discussion of potential effects)
Effects related to other actions in the study area (incorporated into the baseline future or No-
Action forecast scenario; see Chapter 4 for discussion of actions; Chapter 5 for discussion
of potential effects)
Effects related to induced development (see Chapter 5 for a discussion of potential effects)
Regardless of the source, the general techniques for analyzing these effects are similar, and the
magnitude, location, and likelihood of the effects from all sources should be evaluated in tandem.
Techniques for analysis of encroachment alteration effects are, in general, similar to techniques used
to evaluate the direct effects of proposed projects. Primary techniques for analysis include:
? Tables and Matrices - While tables and matrices will not help the analyst quantify individual
effects, presentation of encroachment-alteration effects in tabular or matrix format is helpful
in organizing and summarizing quantitative and qualitative analyses. Measures derived from
quantitative research or judgements derived from qualitative techniques may be summarized
and compared in matrix format. A matrix is also particularly valuable in evaluating the
cumulative effects of multiple actions on resources or categories of resources (CEQ, 1998)
The forms of matrix notation (binary, quantitative, and weighted) are described in Chapter
5. A sample of a matrix developed to summarize the cumulative effects of a proposed action
is presented in Figure IV-6. This table illustrates how direct impacts of a proposed action
may be combined with indirect effects (encroachment-alteration effects and effects related
to induced growth) and the cumulative effect of other past, present, and future actions to
derive the a proposed action's cumulative effects on a variety of resource categories.
? Measures and Indicators - Quantification or characterization of effects on individual
resources can be accomplished through calculation of measures of performance or indicators
of change suitable to particular resources. For example, the fiscal effects of induced
residential growth can be described by showing the net change in government tax revenues
and expenditures for services. The effects of induced growth on ground water can be
evaluated by showing the change in gallons of water consumed per day, a reduction in
aquifer recharge due to an increase in impervious surface, or levels of pollutants or nutrient
Section IV: Analysis Page 1V-32
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
loading. Where precise quantification is not possible or not necessary to enable meaningful
comparison between no-action and action alternatives then approximate ranges or high-
medium-low characterizations can be employed. Examples of indicators appropriate to
measure the effects related to land development are detailed in Figure III-18 in Chapter 5.
? Cartographic Techniques - Successive layers of map overlays depicting notable features and
areas where effects are anticipated can be very effective in evaluating and illustrating
encroachment-alteration effects attributable to proposed actions or induced activity. Habitat
and community fragmentation, land cover alteration and vegetation loss, coverage of
community facility service areas, and effects on viewsheds and historic resources are
particularly amenable to analysis through this technique. By adding maps depicting
community plans and goals for land use and community facilities, the map overlay
techniques can highlight areas of potential conflict between cumulative land use effects and
community goals. Cartographic techniques are described in more detail in Chapter 5.
? Carrying Capacity Analysis - This technique involves determining capacity of resource
systems and the thresholds beyond which sustainability becomes threatened. Once these
thresholds are determined cumulative effects to resources (calculated using the measures and
indicators described above) can be more fully evaluated. This technique is particularly useful
for evaluation of:
- air quality and water quality/quantity;
- wildlife populations;
- infrastructure and community facilities; and
- land use (through evaluation of density and uses permitted in districts and the
likelihood change in future land use plans in response to development pressures).
? Models - Models for calculating the propensity for change within resource systems are
available and can be used in the analysis of indirect and cumulative effects where a
quantitative approach to estimation has been employed. Use of modelscan be helpful
particularly where models have been used in the evaluation of direct impacts and information
quantitative information regarding indirect and cumulative effects can be readily added.
Examples of models that may be employed include (CEQ, 1998):
- air dispersion models;
- hydrologic regime models;
- soil erosion models;
- sediment transport models;
Section IV: Analysis Page IV-33
Guidance on Indirect and Cumulative Impact Assessment Volume II. Practitioner's Handbook
- species habitat models; and
regional economic models.
Modeling techniques can be combined with each of the other techniques described here to
determine carrying capacity and impact measures, or input for matrices or map layers.
Section IV: Analysis Page IV-34
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Work Product of Step 6
The findings of the indirect and cumulative effects analysis must be documented along with a
discussion of the methods employed, why they were selected, and how they were used. The work
product of this step can take the form of a technical memorandum. Figure IV-6 provides a
framework for summarizing a wide-range of direct and indirect effects that may be adapted for
particular analyses.
Section IV: Analysis Page IV-35
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Guidance on Indirect and Cumulative Impact Assessment Volume 11. Practitioner's Handbook
Resources and Supplementary Readings
Delphi Method:
Gamble, T., and D.F. Pearson, 1993, "Growth Allocation Using the Delphi Process, " 4`n National
Conference on Transportation Planning Models Compendium of Papers, Transportation Research
Board, Washington, D.C.
Gravity Models:
Krueckeburg, Donald, and Arthur Silvers, 1974, Urban Planning Analysis: Methods and Models,
John Wiley & Sons, New York City.
Economic Impact Analysis:
Weisbrod, Glen and Burton Weisbrod, 1997, Assessing the Economic Impact of Transportation
Projects: How to Choose the Appropriate Technique for Your Project, Transportation Research
Circular 477, Transportation Research Board, Washington, D.C.
Transportation Research Board Conference Proceedings 21, 2000, Information Requirements for
Transportation Economic Analysis, Washington, D.C.
Hartgen, David T., and Ji Youn Kim, "Commercial Development at Rural and Small Town Interstate
Exits," Transportation Research Record 1649, 1998.
Fiscal Impact Analysis:
Burchell, Robert W., David Listokin, and William R. Dolphin, 1985, The New Practitioner's Guide
to Fiscal Impact Analysis, Center for Urban Policy Research, New Brunswick, NJ.
TCRP Report 39, 1998, The Costs of Sprawl-Revisited, Transportation Research Board,
Washington, D.C.
Integrated Land Use and Transportation Models:
NCHRP Report 423A, 1999, Land Use Impact of Transportation: A Guidebook, Transportation
Research Board, Washington, D.C.
Oryani, Kazem;, and Britton Harris, 1996, Review of Land Use Models and Recommended Model
for DVRPC, Delaware Valley Regional Planning Commission, Philadelphia, PA.
Wegener, Michael, 1994, "Operational Urban Models: State of the Art," Journal of the American
Planning Association, Vol. 60, No. 1, 17-29.
Porter, Chris, Laura Melendy, and Elizabeth Deakin, 1995, Land Use and Travel Survey Data: A
Survey of the Metropolitan Planning Organizations of the 35 Largest U.S. Metropolitan Areas,
Delaware Valley Regional Planning Commission, Philadelphia, PA.
Section IV. Analysis Page IV-37
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
TCRP Report 48, 1999, Integrated Urban Models for Simulation of Transit and Land Use Policies:
Guidelines for Implementation and Use, Transportation Research Board, Washington, D.C.
Lowry, I.S., 1964, "A Model of Metropolis" in S.H. Putman, Urban Residential and Location
Models, Martinus Nijhoff Publishing, 1979.
Goldner, W. 1971, "The Lowry Model Heritage," Journal of the American Institute of Planners, 37,
100-110.
Putman, Stephen H., 1983, Integrated Urban Models: Policy Analysis of Transportation and Land
Use, Pion, London.
Echenique, Marcial H., Anthony D.J. Flowerdew, John D. Hunt, Timothy R. Mayo, Ian J. Skidmore
& David C. Simmonds, 1990, "The MEPLAN Models of Balbao, Leeds, and Dortmund," Transport
Reviews 10:309-22.
Barra, Tomas de la, 1989, Integrated Land Use and Transport Modeling, Cambridge University
Press, Cambridge, UK.
Anas, Alex, 1992, NYSIM: A Model for Cost-Benefit Analysis of Transportation Projects, Regional
Plan Association, New York.
Waddell, Paul, 1999, Urban Sim Reference Manual, www.urbansim.org.
Conrad, Lawrence, and Samuel N. Seskin, 1998, The Costs of Alternative Land Use Patterns,
FHWA.
EPA, 1999, Smart Growth INDEX: A Sketch Tool for Community Planning, Technical Fact Sheet.
Economic and Social Impact Analysis:
Forkenbrock, David J. and Glen E. Weisbrod, (2001) NCHRP Report 456: Guidebook forAssessing
the Social and Economic Effects of Transportation Projects, Transportation Research Board,
Washington, DC.
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Chapter 7
Step 7 - Evaluate Analysis Results
Overview
Assessing the magnitude of indirect/cumulative effects, the goal of the previous step, involved
making several types of assumptions regarding:
? the nature of the impact-causing activities;
? the nature of the cause-effect relationships; and
? how the environment will be affected by the impacts.
The objective of this step is to evaluate these assumptions and the uncertainty they produced so as
to better understand the indirect/cumulative effects. The product of this step should be thorough
documentation of any uncertainty and how that uncertainty may influence the range of indirect and
cumulative effects.
This chapter will:
? describe the issues involved in evaluating analysis results;
? outline a basic technique for analysis evaluation;
? provide criteria to be used in assessing the need for more detailed evaluation techniques; and
? discuss more detailed evaluation techniques including:
- sensitivity analysis, and
risk assessment.
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Considerations
The purpose of the framework to this point has been to outline techniques and procedures for
identifying and estimating indirect/cumulative effects of proposed transportation projects. The goal
of these tasks has been to produce an assessment suitable for informing the decision-making process
and the evaluation of alternatives. There is inherent uncertainty in estimating indirect/cumulative
effects, however, and a risk that the actual outcome will differ from that forecasted. Information
regarding the level of uncertainty in an estimate of indirect/cumulative effects should, therefore, be
communicated to decision makers and the public for consideration along with the results of the
analysis. Similarly, information regarding differences of opinion among stakeholders and experts
consulted with respect to forecasted outcomes should also be disclosed. Included in this disclosure
should be discussion of differences on goals, notable features, indirect and cumulative effects
meriting analysis, and analysis techniques and results. The basic and detailed methods involved in
undertaking this evaluation are discussed below.
Basic Technique for Analysis Evaluation
In circumstances where either substantial indirect and cumulative effects have been found or where
no such effects have been found, it may not necessary to apply some of the more detailed sensitivity
or risk analysis techniques described below, even if detailed techniques have been used in other steps
in the framework. The key criteria in assessing the need for detailed evaluation are:
? whether the analysts or stakeholders believe that there is any level of uncertainty regarding
the underlying assumptions used to estimate the indirect and cumulative effects,
and
? whether changes in the underlying assumptions can be expected to result in significant
changes in the findings.
If uncertainty in the underlying assumptions is recognized but variation in the assumptions is
unlikely to significantly alter the findings then the uncertainty and conclusions regarding sensitivity
should be carefully documented and the analyst may proceed to the final step in the framework.
If analysts or stakeholders see a level of uncertainty in the assumptions employed and that
uncertainty is likely to significantly alter the findings then a more detailed evaluation is warranted.
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Detailed Techniques for Analysis Evaluation
There are two key techniques that are of use in evaluating indirect/cumulative effects analyses:
? Sensitivity Analysis - This procedure involves changing forecast assumptions one at a time
to test the sensitivity of effects to the particular assumptions. In other words, the purpose of
this analysis is to test whether slight shifts in the analytical assumptions would cause larger
changes in the effect, and help clarify degrees of confidence in estimating effects. This
technique is applicable to both qualitative and quantitative assessments. Where multiple
scenarios for the same project or no action alternative have been developed (i.e., best and
worst case), sensitivity of impacts to changes in assumptions is known and this step need not
be repeated.
There are several disadvantages to this method of evaluation. (Lewis, 1995):
- Assumptions and judgements are often varied by arbitrary amounts instead of by
reference to reasoned analysis of potential error. To avoid this, an attempt should be
made to construct reasonable alternative scenarios.
The what-if assumptions or scenarios used in sensitivity analysis do not identify the
probability of alternative outcomes. This is overcome by utilizing risk assessment
techniques (see below).
Worst-case scenarios often assume the highly unlikely event that all assumptions will
deviate from expectations in the same direction, providing less information to the
analyst than a more probable scenario.
? Risk Analysis - This method includes a family of forecasting techniques and planning
processes used to examine risk and uncertainty in alternative courses of action. It is best
performed when quantitative methods have been used. Risk analysis seeks to improve the
quality of information available for decision-making by revealing and clarifying the
implications of uncertainty in technical and analytical decision-support material. There is no
presumption of best or most accurate forecast; rather, the whole range of conceivable
outcomes is arrayed together with the estimated probability of each occurring. Combined
with group-oriented public involvement methods, e.g., a collaborative task force of
stakeholders, risk analysis can promote consensus. In this way, it can bridge gaps between
the forecasting level and the policy level.
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Risk Analysis involves the following steps:
- Identify variables and causal factors - this step has been performed in the
identification and analysis of indirect/cumulative effects.
- Elicit expert/stakeholder opinion on the uncertainty of variable and causal factors -
variables should be restated in ranges to reflect uncertainty, these ranges correspond
to probability distributions. This step is best completed with the assistance of
spreadsheet-based risk analysis software (@RISK by Palisade Corporation is one
example).
- Report results - risk analysis software will take a quantitative model and find the
most likely outcome based on the probability distributions of the variables. Each
output variable will be stated as a probability distribution indicating the range in
which it could be expected to vary and the probabilities of those alternative
outcomes.
Once the level of uncertainty in assumptions and outcomes has been properly explored and
documented the analyst may move on to assessing consequences of indirect and cumulative effects
and discussing options for mitigation.
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Resources and Supplementary Readings
Lewis, D., 1995, "The Future of Forecasting: Risk Analysis as a Philosophy of Transportation
Planning," TR News, No. 177, March-April, pp 3-9.
@Risk, spreadsheet software risk analysis tool, Palisade Corporation, www.palisade.com
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Section IV. Analysis Page IV-44
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
SECTION V
ASSESSING THE CONSEQUENCES
The purpose of estimating indirect/cumulative effects of proposed transportation projects is to
contribute to the body of information that will support a decision about whether
? to proceed with the plan or project, as proposed;
? to formulate a revised plan or project; or
? to otherwise mitigate adverse indirect/cumulative effects associated with the proposed plan
or project.
The objective of this step is to assess the consequences of the analyzed indirect/cumulative effects
and develop strategies to address unacceptable indirect/cumulative effects.
The analysis of indirect and cumulative effects involves the following step of the framework:
Step 8 - Assess the Consequences and Develop Appropriate Mitigation and Enhancement
Strategies
This step and the methodologies appropriate for carrying it out are described in detail in Chapter 8.
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Chapter 8
Step 8 - Assess the Consequences and Develop Appropriate
Mitigation and Enhancement Strategies
Overview
Once the full range of indirect/cumulative effects have been identified and evaluated it becomes
important assess the consequences of effects and determine the need for modifications to avoid
effects, or strategies to mitigate effects.
This chapter will:
outline the considerations involved in assessing consequences, determining the need for
mitigation, and developing a mitigation plan;
provide an illustration of the mitigation decision-making process; and
identify indirect/cumulative effects mitigation techniques that can be used by the sponsoring
agency or recommended to outside agencies, as appropriate.
Considerations
When assessing the consequences of an indirect/cumulative effects analysis and the need for
mitigation or enhancement measures, there are several major considerations:
? Does the analysis of effects provide a reasonable basis for informed decision-making?
? Are there significant effects that are seen as unacceptable?
? Are there practicable mitigation/enhancement measures?
? Are mitigation/enhancement measures within the jurisdiction of the sponsoring agency?
? What is the sponsoring agency's role when mitigation/enhancement measures are not within
its jurisdiction?
These considerations are discussed in detail below.
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Guidance on Indirect and Cumulative Impact Assessment Volume IL Practitioner's Handbook
Providing the Basis for Informed Decision Making
Uncertainty can lead to controversy regarding indirect/cumulative effects. There is an obligation to
ensure that the descriptions and analysis in the indirect/cumulative effects analysis are reasonable
and accurate. One of the tests for reasonableness deals with the resolution of controversy. Should
the question (e.g., degree of impact, likelihood of impact) have two sides, each with reasonable
arguments, then the agency NCDOT obligation is to reveal both sides of the matter and, using
NCDOT or outside agency, choose between the sides. The key is to disclose the controversy and to
make a reasonable choice on the impacts.
The review of case law discussed in Volume I indicates a requirement that mitigation of effects
(direct, indirect, and cumulative) must be discussed in an EIS "in sufficient detail to ensure that
environmental effects have been fairly evaluated" (Robertson v. Methow Valley Citizens Council,
490 U.S., 332, 252 (1989)). The EIS must describe mitigation that could be undertaken by either
the agency itself or by other entities over which the agency has no control. However, the agency is
not required to implement any of the mitigation ideas itself, or to receive implementation
commitments from other entities.
Determining When a Potential Impact May Be Considered Unacceptable
Guidance for determining what is unacceptable can be found in the initial steps of the
indirect/cumulative effects assessment process, i.e., the goals and notable features identification (see
Step 2 - Chapter 2). If the analysis indicates that the proposed project could produce effects that
would conflict, delay, or interfere with a study area goal identified in Step 2, then the proposed
project, or the activity of the project responsible for that effect, is potentially unacceptable. Step 2
also suggests that the goals identification process attach relative importance to each relevant goal.
Effects that would conflict, delay or interfere with relatively important goals should be considered
significant in the local context.
Relative importance is also helpful for dealing with uncertainty. Experience indicates that if
something of extreme importance could be affected through a chain of causality linked to a proposed
project, then there will likely be reaction to the effect regardless of the degree of uncertainty about
whether the effect will really occur. As one commentator notes, "Whether a specific use of the land
in reality causes any economic or social problems may not be as important as what people perceive
the problem to be." (Loundsbury, 1981) The message for indirect/cumulative effects assessment is
that the goals identification should not be treated lightly, as it lays the foundation and context for the
entire assessment.
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Mitigation for Impacts to Notable Features
Depending on the project circumstances, mitigation of indirect/cumulative effects on notable features
may also require consideration. It is suggested that such consideration occur when one or more of
the following circumstances exist:
? The effect could worsen the condition of a notable feature considered sensitive or vulnerable.
? The effect could interfere with or delay the planned or required improvement of a notable
feature.
? The effect could eliminate a notable feature that is valued or unique, or render the valued or
unique feature ordinary.
? The effect is otherwise inconsistent with an applicable law.
Determining the Practicability of Mitigation
As with mitigation of direct effects, mitigation of indirect/cumulative effects is not always
practicable. The U.S. EPA's Section 404(b)(1) Guidelines (40 CFR 230) provide a definition of the
term "practicable" with respect to project alternatives as available and capable of being done after
taking into consideration cost, existing technology, and logistics in light of overall project purposes.
These considerations should be part of the evaluation of alternatives to avoid or minimize an indirect
effect, or other form of mitigation.
Responsibility for Mitigation and the Role of the Sponsoring Agency
The essence of the responsibility issue is whether the indirect effect is within or outside the control
of the sponsoring agency. This issue was a subject of debate in the U.S. EPA's promulgation of its
"General Conformity Rules" (FR 63214-63259). These rules require that federal agencies make
determinations that each of their agency's federal actions conform to the state implementation plan
for attaining and maintaining air quality standards. In developing the rules, many federal agencies
stated that it is unreasonable to withhold a conformity determination where it is impracticable for
the federal agency to remedy the situation. The U.S. EPA concluded that it would be unreasonable
to interpret the Clean Air Act as requiring federal agencies to take responsibility for emissions that
they cannot practicably control and for which they have no continuing program responsibility.
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The U.S. EPA used the Supreme Court's analysis in its 1989 decision in Robertson v. Methow Valley
Citizens Council (409 U.S., 109 S.Ct. (1989)) to support this conclusion (see 4.0 Case Law, Volume
I, Section I). In that case, which involved the Forest Service's issuance of a special-use permit to a
private developer, the imposition of the mitigation plan was within the jurisdiction of state and local
agencies not the sponsoring agency. The court held that: "it would be incongruous to conclude that
the Forest Service has no power to act [on issuing the permit] until the local agencies have reached
a final conclusion on what mitigation measures they consider necessary."
However, the court added that the federal agency in such circumstances does need to advise the state
and local agencies with mitigation authority as to what it considered appropriate mitigation. This
advice is considered part of the federal agency's NEPA responsibility.
Mitigation responsibility for indirect/cumulative effects of transportation projects proposed by
NCDOT is based on the distinction between those effects that are within the control of the project
agency and those that are outside the control of NCDOT, to the extent that such distinction is
consistent with federal and state laws. The typology for distinguishing indirect/cumulative effects
outlined in Volume I is consistent with this approach. Specifically, "encroachment-alteration"
effects can be equated to "within the control" of NCDOT, while "induced growth and effects related
to induced growth" are generally "outside the control" of NCDOT (the exception being to avoid or
minimize impacts through change in access location, where practicable). Indeed, the U.S. EPA used
airport expansion and adjacent development of an industrial park as an illustrative example of federal
control within the preamble to its "General Conformity" rule. In the example, development of the
industrial park is known to depend on FAA approval of the airport expansion. Under the Framework,
the airport expansion is a project that "would likely stimulate land development having
complementary functions." For purposes of Clean Air Act conformity, the example notes that the
FAA is responsible for emissions from airport-related activities but is not responsible for emissions
from the industrial park. Within the context of the indirect assessment framework, however, the FAA
would be responsible for analyzing the industrial park and its effects and recommending mitigation
if such effects would be unacceptable.
Among those indirect/cumulative effects generally within the control of NCDOT are:
? Generally, those indirect/cumulative effects associated with the location of the project and
its access provisions;
? Effects related to how the project is constructed, e.g., modification of regime, land
transformation and construction, land alteration, resource extraction, etc.; and
? Effects related to how the project right-of-way will be used and maintained, e.g., traffic and
traffic-related effects, fertilization, chemical deicing, weed control, pest control, etc.
Section V. Assessment Page V-6
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Methods
The primary method for assessing consequences and developing mitigation consists of a set of steps
where each identified indirect effect is evaluated in the context of the overall aim of the project and
study area goals and notable features. This process and the steps of the indirect/cumulative effects
assessment framework leading up to it are illustrated in Figure V-I.
An effect that would adversely impact a study area goal or notable feature may require mitigation.
If a mitigation effort is impractical, NCDOT should fully document the reasons for the
impracticability of mitigation.
If practical mitigation alternatives do exist, NCDOT determines whether such efforts are within its
control or jurisdiction. For example, many mitigation efforts relevant to induced growth and its
consequences are within the control of municipal and county agencies, not NCDOT. In these cases,
it is the responsibility of NCDOT to identify and assess potential effects, recommend strategies for
mitigation, and re-evaluate the extent of the effect if such mitigation efforts were implemented.
If mitigation strategies are within the jurisdiction of NCDOT should document its mitigation plan
and how such mitigation efforts are expected to ameliorate adverse indirect/cumulative effects.
Potential mitigation techniques relevant to the major categories of indirect/cumulative effects and
example applications of those techniques are outlined below.
Section V. Assessment Page V-7
Figure V-1
Indirect Effects Evaluation Framework and
Process for Assessing Effect Consequences and
Developing Mitigation/Enhancement Strategies
Steps 1 through 4 - Scoping and Data Gathering
Determine study area boundaries, goals, and notable features, and identify project impact
causing activities.
Step 5 - Identify Potentially Significant Effects
Does effect merit detailed analysis?
l Yes - Proceed to next steps
No Further analysis of effect
? not required.
End evaluation.
Steps 6 and 7 - Analyze Indirect Effects and Evaluate Analysis
Analyze potential effects to determine magnitude, duration, location and likelihood.
Step 8 - Assess Consequences and Develop Mitigation
Does the effect conflict with notable features or
study area goals?
1 Yes
Is mitigation practicable?
1 Yes
Are the consequences within Agency's control?
Yes
Integrate mitigation into
project/plan.
Re-evaluate effect.
No
10 Mitigation not required.
End evaluation.
No
0 Document impracticability.
End evaluation.
No
1101 Recommend mitigation to
agencies that have
jurisdiction.
Re-evaluate effect.
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
Mitigation Techniques for Encroachment-Alteration Effects
Encroachment-alteration indirect/cumulative effects, although often distant in time and space from
the project, are similar to many direct project effects and can be addressed with similar mitigation
strategies. As with direct effects, in many cases these strategies involve altering one of the following
aspects of the project or plan within the control of the NCDOT:
? Facility type
? Facility alignment
? Facility design features
? Techniques used during construction
? Facility maintenance
Mitigation Techniques for Induced Growth
The three broad types of project induced growth can be mitigated to some extent through a variety
of access control by NCDOT or land use control techniques by local municipalities. These
techniques are described below as they relate to the primary types of induced growth. It should be
noted that not all regulatory techniques are available for use in all jurisdictions due to the structure
of local land use laws.
Techniques Available to the NCDOT
There is one primary technique in which NCDOT can work under its own authority and initiative
with local government to influence the magnitude and location of induced growth activity:
? Access Management - The extent and location of complementary development and regional
development shifts can be controlled to some extent through modifications to the access plan
for the facility. For highway facilities, aspects of the project that can be modified include the
location of interchanges, the type of the interchange (partial, one-way access or full access),
connectivity to local arterials, traffic patterns on connecting roadways, the presence of
frontage roads, and curb-cut regulations on connecting roadways. For transit facilities the
location of stations, and the type of service, and frequency of stops can be modified. Some
of these features such as the type and location of interchanges are within the jurisdiction of
the sponsoring agency. Other issues, such as traffic patterns and curb-cut regulations may
be within the jurisdiction of local agencies.
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Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Techniques Available to Other Entities
Several techniques for regulating and managing growth induced by a proposed project or other
actions are available for implementation by local governments and other agencies. Where induced
growth has been determined to be an issue requiring mitigation, the EIS must describe techniques
for growth management that may be implemented by other parties. These techniques fall into the
following general categories:
? Zoning/Comprehensive Planning - Local zoning controls and comprehensive planning are
outside the jurisdiction of the NCDOT but are often the most effective tools at controlling
induced growth. Zoning involves the regulation of both the density and use to which land
may be put. When combined with comprehensive planning, zoning allows communities to
shape patterns of growth and development within their boundaries.
To use zoning and planning effectively as a tool to mitigate project induced growth, the land
planning process should ideally run concurrent with the transportation planning process. If
the land planning process occurs at a later time, particularly in areas in that are clearly in the
path of future development, anticipation of the project among developers and land holders
may make the planning process more difficult. NCDOT can play a role in this process by
encouraging local agencies to consider transportation facilities in land use planning through
early consultation and coordination with local governments throughout the planning and
environmental review process.
A zoning response to a transportation plan or project is also most effective when it involves
an area-wide or region-wide approach to distinguishing areas suitable for growth from those
requiring conservation. In circumstances where numerous planning juri sdictions are present
in the impact area the involvement of NCDOT or another regional planning agency may be
necessary to produce a coordinated response.
In cooperative efforts with local governments and agencies it should be noted that zoning
regulations enacted as a response to the induced growth effects of transportation facilities
should balance other needs of the community including employment and housing for all
income groups.
? Growth Management Regulation- Several jurisdictions have pursued regulatory strategies
that allow for regulation of the timing and location of residential and commercial
development in a manner not addressed by traditional zoning regulations. Examples of
growth management techniques that may be suggested for implementation in North Carolina
include the following.
- Adequate Public Facilities Ordinances (APFOs) - This type of growth management
strategy links approval for certain types of projects (those requiring subdivisions or
Section V: Assessment Page V-10
Guidance on Indirect and Cumulative Impact Assessment Volume H. Practitioner's Handbook
variances, for example) to a review of the capacity of infrastructure to serve those
projects. Infrastructure types often considered in these ordinances include
water/sewer service, local transportation facilities, and other government services.
Long range plans for the programming of infrastructure projects in Capital
Improvement Plans are prepared as part of the ordinance and projects exceeding the
capacity of infrastructure before improvements will be in place do not receive
approval. Conditional approval of subdivisions based on provision of infrastructure
at the developers expense (exactions) is provided for under North Carolina law but
ordinarily limited to streets, utilities, and parks, and does not cover schools, fire
stations, or other community facilities. Requirements for the dedication of land (for
purposes other than parks or utility easements) or the payment of impact fees is not
expressly provided for under North Carolina law. (Lawrence & Wicker, 1996).
Development Moratoria - Similar to APFOs, moratoria give local jurisdictions the
authority to halt new development projects until public facilities are improved to an
appropriate level. Moratoria have also been used to preserve corridors slated for
transportation improvements.
Urban Growth Boundaries - Some metropolitan regions outside of North Carolina
have adopted growth boundaries surrounding metropolitan areas to preserve open
space around cities, slow the growth of suburban sprawl, and focus development into
urban cores where infrastructure levels provide capacity for growth. These growth
boundaries are often designed to accommodate growth projected for twenty to thirty-
year periods. Growth boundaries are effectuated by strictly regulating densities
outside the growth boundaries or limiting the provision of infrastructure beyond the
boundary (planning techniques that are permissible under North Carolina law).
Regional authorities are often given the responsibility of regulating and planning the
growth boundary system. Formal regional management of growth beyond county
boundaries would likely require special enabling legislation in North Carolina.
Portland, Oregon's experience shows that growth boundaries can be successful in
preserving green space and promoting development of the core, but regulations need
to be reviewed frequently to prevent spillover growth just outside protected areas.
Extraterritorial Zoning/Annexation - In some fast growing metropolitan regions,
cities are given special authority over zoning issues and development applications in
unincorporated areas outside city limits. Annexation and extraterritorial zoning
powers are provided for under North Carolina statute. (Lawrence & Wicker, 1996).
This authority is meant to promote the orderly growth of the metropolitan area and
compatibility between the city center and the periphery. Extraterritorial zoning
authority is also granted with the expectation that city boundaries will eventually
expand to keep pace with urban development. Policies meant to ease the process of
annexation of incorporated or unincorporated suburban or fringe lands into a city's
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
jurisdiction can mitigate against the induced growth impacts of transportation
improvements by allowing planning, zoning, and growth management strategies to
be implemented on a regional basis.
Mitigation Techniques for Effects Related to Induced Growth
In addition to managing residential and commercial growth induced by a transportation project, a
local jurisdiction may also choose among strategies designed to mitigate the environmental and
social effects related to induced growth.
Techniques Available to NCDOT
Context Sensitive Design - A major goal of context-sensitive design is to allow for local
public input early in the design process so that costly delays and revisions can be avoided.
Examples of context sensitive design and flexible standards include, deviation from the
standard length of an acceleration or deceleration lane to protect a notable feature, modifying
the design of an arterial that passes through a downtown area to allow for a boulevard that
would better fit with the local context, and inclusion of special materials or design features
to allow the facility to fit the scale and style of its surroundings.
Techniques Available to Other Entities
? Resource Management and Preservation Regulations - Specific regulations designed to
protect vital resources can work to guide the path and intensity of development and limit
impacts on notable features related to induced growth. There are several examples of
implementation of resource management in North Carolina. General categories include:
- Coastal areas where development areas are delineated and development is permitted
only under special circumstances in critical areas.
- Stream buffers where development is regulated to protect the quality and quantity of
water resources, prevent flooding, and promote water-related tourism and recreation.
Performance Standards - North Carolina law makes provision for the use of performance
standards in local zoning and subdivision regulations. Performance standards can define uses
as-of-right or the standards required for obtaining a conditional use permit. Performance
standards encompass the following types of regulation.
Regulation of height, bulk, setback, lot size and other dimensional features.
Regulation of uses within zones and standards that define and distinguish uses.
Section V: Assessment Page V-12
Guidance on Indirect and Cumulative Impact Assessment Volume IL Practitioner's Handbook
Specification of site design features such as off-street parking, impervious surface,
vegetative cover removal, landscaping and screening, signage.
- Specifications of standards for noise and pollutant emissions allowed in
manufacturing or agricultural activities.
- Standards forcommunity appearance or historic preservation with review and limited
enforcement powers vested in a planning agency or special commission.
? Land Acquisition/Conservation Easements - A technique for preservation of green space,
habitat, or other important resource areas that is seeing increasing use is the acquisition of
land or development rights by government agencies, non-profit groups, or other private
initiatives. These groups purchase or accept donations of land and pledge to keep the land
permanently undeveloped. Development rights can also be purchased while the underlying
title and use is retained by a landholder through the use of conservation easements. These
easements once written into the a deed can permanently prevent development on a parcel
regardless of future ownership. Carefully planned acquisitions can work to focus growth and
protect notable features from growth related impacts.
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Guidance on Indirect and Cumulative Impact Assessment Volume 11: Practitioner's Handbook
Techniques for the Systems Planning Stage
Many of the techniques outlined above are applicable to the transportation systems planning as well
as to project development. As noted above, comprehensive planning, resource preservation
regulations, and other techniques meant to shape growth, when integrated with the planning of
transportation systems will minimize the likelihood of indirect/cumulative effects on notable features
and conflicts with community goals. There are some additional techniques applicable to
transportation systems planning that may be useful, however.
? Comprehensive Performance Measures - Traditionally in the planning of transportation
systems, the assessment of need for a transportation project has been based in part on
measures of mobility in the existing transportation system. These measures focus on the
efficient movement of vehicles. This is often measured in level of service (LOS) ratings
describing various states of traffic conditions. Mobility measures provide no linkage,
however, with land use conditions in the vicinity of projects. This disconnect can lead to
the potential for conflict with notable features or goals later in the process. Evaluating
projects with performance measures related to accessibility will help better connect
transportation needs, land use considerations, and concerns regarding sustainability. Such
measures include:
Vehicle Miles Traveled (VMT) or Vehicle Hours Traveled (VHT)
Accessibility to jobs and commercial centers
- Impact on Jobs/Housing Balance
The use of integrated transportation and land use models that employ a feedback loop
between transportation and land use choices will also help integrate evaluation of induced
growth concerns into the systems planning process.
? Promoting Regional Coordination - As discussed throughout this handbook, early
coordination on a regional level is the best method for evaluation and mitigation of
indirect/cumulative effects. Regional coordination is especially important in controlling
induced growth because a variety of uncoordinated local regulatory responses may work to
intensify effects in the least regulated areas.
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Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Work Product of Step 8
The product of assessing the consequences and developing mitigation should consist of
documentation: the comparison of indirect/cumulative effects to the relevant goals and notable
features (i.e., the assessment of consequences); the mitigation strategy developed to address any
unacceptable indirect/cumulative effect; or mitigation considered and reasons why mitigation is not
practicable. The documentation should note what the mitigation entails, its anticipated effectiveness,
how it should be implemented, and who is responsible for implementation. It should also be shared
with those having a stakeholder interest in the studied effect and mitigation, as well as those
responsible for ultimately implementing the mitigation, if responsibility lies outside NCDOT's
purview. Completion of this last step in the indirect/cumulative effects assessment process will
allow for full documentation of the process in a transportation plan or project environmental
documentation.
Section V. Assessment Page V-15
Guidance on Indirect and Cumulative Impact Assessment Volume II: Practitioner's Handbook
Resources and Supplemental Readings
American Farmland Trust (1997), Saving American Farmland: What Works, Washington D.C.
Edward Beimborn, Smitha Vijayan, Alan Horowitz, and Melissa Bordewin (1999), "Alternative
State Approaches to Transportation/Land Use Interactions," Center for Urban Transportation
Studies, University of Wisconsin-Milwaukee.
Environmental Protection Agency, "General Conformity Rules" (FR 63214-63259)
Bosselman, Fred P., Craig A. Peterson, and Claire McCarthy (1999), Managing Tourism Growth:
Issues and Applications, Island Press, Washington, D.C.
Krizek, Kevin, and Joe Power (1998), A Planner's Guide to Sustainable Development, Planning
Advisory Service Report Number 467, American Planning Association, Washington, D.C.
Lawrence, David M., and Warren Jake Wicker (1996), Municipal Government in North Carolina,
Second Edition, Institute of Government, University of North Carolina at Chapel Hill.
Litman, Todd (2000), "Transportation Market Reforms for Sustainability," Transportation Research
Record, No. 1702, Transportation Research Board, Washington, D.C.
Livable Communities Initiative (2000), Building Livable Communities: Sustaining Prosperity,
Improving Quality of Life, and Building a Sense of Community, www.livablecommunities.gov.
Loundsbury, J. F. (1981), "The Nature of Land Use Problems in the United States," Land Use: A
Spatial Approach, Loundsbury, J. F. ed., Kendall Hunt, Dubuque, IA.
Porter, Douglas R.(1997), Managing Growth in America's Communities, Island Press, Washington,
D.C.
Section V: Assessment Page V-16
Appendix A
Sample Survey Instrument
PURPOSE
The purpose for implementing the Potential Development Questionnaire is to gain insight
from local and regional professionals into the study area's economic and development
patterns in order to assess how future economic and physical development patterns will
be affected by the Project.
Interviewee:
Title:
Affiliation/ Company:
Phone Number:
INFRASTRUCTURE & DEVELOPMENT
1. Please list what you perceive to be the potential significant development projects in the
study area that will be constructed by the Year 2025 using the attached table.
Additionally, please indicate how each projects' probability of development increases or
decreases due to the completion of each section of the Northern Beltway. This list should
include projects under construction, pending approval and other proposals you believe
will have a reasonable chance of being constructed by the Year 2025.
2. Do you think that the study area's current zoning and land use plans sufficiently address
future development needs and transportation improvements? If no, please explain what
zoning and/or land use plans you think are necessary.
Yes _No
3. What issues and concerns regarding land use and transportation infrastructure
development in the study area do you perceive as most important in the region?
Additionally, do you interpret these issues and concerns as being sufficiently addressed in
the comprehensive plans? Please specify.
4. Do you anticipate that there will be a future land use and development pattern scenario
with the Project that differs from the future scenario without the Project? If yes, please
describe below and indicate areas that may be affected on the attached Map #l.
_Yes _No
A 7
Appendix A
Sample Survey Instrument
5. We would like to determine the potential for zoning changes or infrastructure changes in
the event that the Project is implemented. In your opinion, would the Project affect the
future zoning or infrastructure plans in the study area?
_Yes _No (If No, please skip to Question 7)
6. In your opinion, what areas of the study area, if any, would be first targeted for rezoning
in order to accommodate future demand and need? Please indicate on attached Map #2.
What types of changes (i.e., density or use type)?
7. Do you anticipate that the Project will promote additional capital investments to support
future development that otherwise would not be made? Please explain and identify on
Map #3 the areas and type of infrastructure improvement (i.e., water, sewer)
_Yes _No
Would you anticipate that the Project will affect the demand for available development
parcels or planned/proposed development projects?
_Yes _No
9. If you answered Yes to Question 8, what is the likelihood of the Project influencing
timing or status of planned development projects?
-High -Low
Appendix A
Sample Survey Instrument
COMPETITIVE STRATEGIES AND ACCESSIBILITY
10. How do you see the First Phase of the Project influencing traffic and transportation
patterns and what industries and/or populations will it most affect, and in what way?
11. How do you see the Second Phase of the Project influencing traffic and transportation
patterns and what industries and/or populations will it most affect, and in what way?
12. What types of industries and business will be most affected by construction of the:
First Phase
Second Phase
13. What are some of the competitive strengths that the study area has over other counties in
North Carolina? What are some of the weaknesses? (i.e., in terms of technology, the labor
pool, industrial base, etc.)
Strengths:
Wealuzesses:
A 2
Appendix A
Sample Survey Instrument
14. How significant a role does transportation and accessibility play in residential, commercial
and industrial development in the study area?
15. Do you think that either or both Project Phases will improve travel time and reliability in
the study area? If yes, what impacts would you anticipate this improvement would
generate?
16. How do you think the study area will respond to current and predicted national and regional
changes in industrial and commercial trends? What additional support, suppliers, etc. will
these industries need?
17. How does access to the study area affect its competitive advantages in relation to other
North Carolina cities?
18. In your opinion, how will industry and business trends in the study area change by 2025 if
a) the First Phase of the Project is not built? b) the Second Phase of the Project is not built?
and c) no significant improvements are made to the roadway network?
a)
b)
A A
Appendix A
Sample Survey Instrument
c)
19. What other persons do you recommend we contact to receive informed opinions regarding
the economical and development impacts of the Project?
Person Affiliation Contact Information
A I
CA
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