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Transportation Conformity: A Basic Guide for State & Local Officials

Description of a Conformity Determination

For metropolitan transportation plan and TIP conformity, the determination shows that the total emissions from on-road travel on an area’s transportation system are consistent with goals for air quality found in the SIP. Before a SIP is available, other tests of conformity are used. For project-level conformity, a project must come from a conforming metropolitan transportation plan and TIP, its design concept and scope must not have changed significantly from that in the metropolitan transportation plan and TIP, and it addresses potential localized emissions impacts.

A conformity determination demonstrates that implementation of the metropolitan transportation plan, TIP, or project will not cause any new violations of the air quality standard, increase the frequency or severity of violations of the standard, or delay timely attainment of the standard or any interim milestone.

Updated: 4/5/2017
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