Methods for Assessing Transportation-Related Secondary and Cumulative Impacts to Wildlife Communities and Habitat

Focus Area

Wildlife & Ecosystems


Natural Resources







Research Idea Scope

TERI Database Administrator Notes:  Not recommended at present time by 2009 Natural Systems Subcommittee.   Subcommittee recommended funding ID#86, which addresses similar issues.

The proposed research will use existing data (e.g., aerial photography, GIS, and comprehensive
plans) that provides a history and chronology of changes around transportation projects and
analyzes the relationship of this development to the project. The research will identify a number
of transportation projects in several ecoregions for a variety of project sizes and complexities.
The research will document the changes that take place within the area following completion of
each of the projects. The data collected will include:

• Preproject conditions at the site,
• Land use,
• Wildlife population habitat types and condition,
• Water quality and quantity,
• Human population and infrastructure, and
• Postproject changes, planned land use (e.g., comprehensive plans), and zoning over time.

The project will then analyze the data and develop

• Methodology and guidance in identifying, qualifying, and quantifying secondary and
cumulative impacts associated with a transportation project on ecosystems.
• Method and guidance to help identify responsibility for development or its control.

Urgency and Payoff

Transportation projects are required by federal and state law to consider the secondary and
cumulative impacts associated with a project. Several issues arise from this requirement. One is
identifying the relationship among the transportation project, local land use plans and zoning,
timing of development in the area, and responsibility for the mitigation of adverse impacts. A
second issue is the lack of suitable methodologies for quantitatively or qualitatively identifying
secondary impacts and the magnitude of their cumulative effects.

The transportation agency is expected to mitigate secondary impacts associated with
future development within the project area. However, there is no body of information that
identifies the land use impacts and changes that are attributable to transportation projects. In
situations where local land use planning encourages development, it is difficult to determine
where the responsibility for mitigation lies. Transportation projects are often responsible for
development that takes place after completion of a project, even though development of an area
is often encouraged or predetermined through the actions of the local planning agency or through
land use planning and zoning.

Suggested By

Transportation Research Board 2002 Environmental Research Needs Conference Notes

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