Requirements
The Indianapolis MPA lies within a Central Indiana area designated as an Orphan maintenance area, which was defined in the February 2018 South Coast Air Quality Mgmt. District v. EPA court decision as areas that were maintenance areas for the 1997 ozone NAAQS at the time of its revocation (80 FR 12264, March 6, 2015) and were designated attainment for the 2008 ozone NAAQS in EPA’s original designations for this NAAQS (77 FR 30160, May 21, 2012). The Orphan maintenance area includes nine Central Indiana counties: Marion, Boone, Hamilton, Madison, Hancock, Shelby, Johnson, Morgan, and Hendricks counties. This airshed is identified as attainment for all other pollutants.
The IMPO currently monitors air quality and reports on transportation conformity for our region.
In accordance with the 23 CFR part 450 and 40 CFR 51.390, an Interagency Consultation Group (ICG) been formed to oversee transportation conformity analysis, and public consultation is included in the review of the projects and transportation conformity analysis results. The ICG includes representatives from the Indiana Department of Transportation (INDOT), the Madison County Council of Governments, the Columbus Area MPO, the Indianapolis Department of Public Works (DPW), the Indiana Department of Environmental Management (IDEM), and others.
The following documents act as guidelines for the ICG.
Reports and Findings
Most amendments to the MTP and IRTIP require an updated Transportation Conformity Finding. Below are the Transportation Conformity Reports and Conformity Finding Letters for the original and each applicable amendment of the MTP and IRTIP.
2024Q4 – Original CIRCLE 2050 MTP
2024Q4S Transportation Conformity Determination Report | November 2024
USDOT 2024Q4S Transportation Conformity Finding Letter | Received: January 2025
2025Q1 – CIRCLE 2050 MTP Amendment 1
2025Q1 Transportation Conformity Report | January 2025
USDOT 2025Q1 Transportation Conformity Finding Letter | Received: April 2025
2025Q2 – INDOT STIP FY26-30
2025Q2 Transportation Conformity Report | March 2025
USDOT 2025Q2 Transportation Conformity Finding Letter | Received: July 2025
2025Q3 – CIRCLE 2050 MTP Amendment 2
2025Q3 Transportation Conformity Report | July 2025
USDOT 2025Q3 Transportation Conformity Finding Letter | Received: September 2025
2026Q1 – CIRCLE 2050 MTP Amendment 3
2026Q1 Transportation Conformity Report | February 2026
USDOT 2026Q1 Transportation Conformity Finding Letter | Pending
2026Q2 – TIP Amendment
2026Q2 Draft Transportation Conformity Report | March 2026
USDOT 2026Q2 Transportation Conformity Finding Letter | Pending
Projects Outside the MPA
The following is a compiled list of INDOT projects located outside of the Metropolitan Planning Area but within the Transportation Conformity Area (aka the “donut area”). These projects have been reviewed by the Interagency Consultation Group as part of the Transportation Conformity review process.
INDOT Donut List Projects, 2026-2029 STIP, v2026-03-26