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Transportation Conformity: A Basic Guide for State and Local Officials

Purpose of this Guide

This Guide was prepared to help State and local officials understand transportation conformity and how conformity requirements relate to transportation investments in their communities. Specifically, we discuss the implications of conformity on metropolitan transportation plans, transportation improvement programs (TIPs), and transportation projects. The Guide provides overview information on the major elements of the conformity process and provides answers to basic questions.2 Several exhibits are included in the Guide to illustrate key elements of the conformity process. Appendices are also included that discuss the health effects of pollutants, options to reduce on-road mobile source emissions, and resource agency contacts.

2 Many additional documents and training materials are available at and that address the technical requirements of transportation conformity.

Updated: 3/14/2012
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