Methodologies for Estimating Cumulative and Indirect Needs at the System Level

Focus Area

Indirect Effects/Cumulative Impacts


Air Quality, Environmental Process




Under $99k



Research Idea Scope

Identify an assessment method to determine regional cumulative impacts.  Identify what are cumulative impacts in both spatial (region) and timeframe (horizon- year) terms.  Develop sample matrix or other tools to identify what is appropriate analysis for different situations.

TERI Administrator Note (June 2007): Research Need Met

Research for the AASHTO Standing Committee on the Environment. Task 11. Secondary/Indirect and Cumulative Effects Analysis

The objective of this study is to review, summarize and evaluate statutory and regulatory requirements and implementing guidance related to assessment and mitigation of secondary/indirect and cumulative impacts of transportation projects.

Colorado DOT, Areawide Coordinated Cumulative Effects Analysis (Research Underway)

Within a metropolitan planning region, there are a number of issues pertinent to a cumulative environmental effects analysis common to a number of individual NEPA-compliant documents. Conducting individual cumulative effects evaluations within the same area of impact is redundant and a waste of resources. The product of this study will facilitate the preparation of project-level environmental documents and should generate substantial savings in terms of time and money for the participating and affected agencies.

Urgency and Payoff

This research will assist DOTs in addressing cumulative and indirect impacts in the planning process as opposed to NEPA.

Suggested By

Tim Hill, SCOE Environmental Process Subcommittee

[email protected]