About Transportation Conformity
Transportation conformity is the process that links the State Implementation Plan (SIP) with the regional roadway planning, which occurs in the Regional Transportation Plan (RTP) and the Transportation Improvement Program (TIP). It is demonstrated when projected regional emissions from the transportation plan do not exceed the region's motor vehicle emissions budgets stated in the SIP.
While the MPO is ultimately responsible for making sure a conformity determination is made, the conformity process depends on federal, state, and local transportation and air quality agencies working together to meet the transportation conformity requirements.
A new conformity determination must be performed any time a transportation plan is amended in a significant manner, when a region's or state’s air quality goals change, and/or every four years.