Clean Air Act Conformity: the link between Air Quality and Transportation Planning

The air quality conformity determination establishes the compatibility between the state implementation plan, the regional transportation plan and transportation improvement program. The transportation plan includes the region’s guide for transportation system development over a twenty-year period. The Transportation Improvement Program (TIP) includes the region’s choices for Federal spending on expansion and preservation of the transportation system over a four to five year period. The State Implementation Plan (SIP) includes strategies for attainment and maintenance of the National Ambient Air Quality Standards (NAAQS). The conformity determination is based on a regional emissions analysis that demonstrates compatibility among these three planning documents.

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Air Quality Conformity Technical documents supporting the 2040 Comprehensive Regional Plan Update Companion and FY 2018 to 2021 Transportation Improvement Program.

  • Air Quality Conformity Determination for Lake and Porter Counties (original conformity determination dated May 18, 2017): PDF  |  HTML
  • Air Quality Conformity Determination for LaPorte County (amendment dated February 21, 2019):  PDF  |  HTML

Vehicle Emissions Educational Event (2/7/2020) Presentations: