Guide to Use of Tier I Environmental Impact Statements for Transportation Projects

Focus Area

NEPA Process


Environmental Process




Under $99k



Research Idea Scope

TERI Administrator Note (January 2009): Funded as NCHRP Project 25-25, Task 38, “Guide to Use of Tier I Environmental Impact Statements for Transportation Projects.” Completion date October 2008.

The National Environmental Policy Act (NEPA) permits Environmental Impact Statements
(EISs) to be performed in tiers or stages. Tier I of an EIS would typically examine a range of alternatives at a transportation corridor or system level. The current emphasis on environmental stewardship and environmental streamlining is resulting in more frequent use of Tier I EISs early in the transportation project planning process. NEPA and its implementing regulations, however, provide little guidance about when the preparation of a Tier I EIS is appropriate, the level of analyses needed, and the tools necessary to perform the analyses. The research will examine selected case studies to determine

• The circumstances under which Tier I EISs were prepared,
• The tools used to prepare Tier I EISs,
• Whether the use of a Tier I EIS facilitated the choice of multimodal alternatives,
• Whether or how Tier I EISs addressed the issue of secondary and cumulative impacts,
• Whether Tier I EISs resulted in environmental streamlining and environmental

Current constraints and issues regarding the use of Tier I EISs, as well as unexpected
outcomes, will be reported. Among the topics to be examined is the use of a Memorandum of
Agreement designed to:

• Promote an understanding of the decisions that a Tier I EIS could cover,
• Discuss the appropriate role of other agencies in a Tier I EIS process, and
• Describe a Tier I EIS’s relationship to follow-on environmental documentation.

Products will include criteria for when the use of a Tier I EIS is appropriate, a framework
template for the contents of a Tier I EIS, and guidance on how to perform meaningful impact analyses that meet legal and environmental regulatory requirements.

Suggested By

Transportation Research Board 2002 Environmental Research Needs Conference Notes

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