Air Quality Conformity

Transportation conformity provisions of the Clean Air Act Amendments require metropolitan planning organizations (MPOs) to make a determination that the Long Range Transportation Plan (LRTP), which is also known as the Metropolitan Transportation Plan (MTP), Transportation Improvement Program (TIP), and the projects conform to the State Implementation Plan (SIP) and that regional emissions will not negatively impact the region’s ability to meet the National Ambient Air Quality Standards (NAAQS).

Conformity to the SIP means that the region’s LRTPs and TIPs 1) will not cause any new violations of the NAAQS; 2) will not increase the frequency or severity of existing violations; and 3) will not delay attaining the NAAQS.

Air Quality Conformity Report for 2050 Metropolitan Transportation Plan (MTP)

As part of its transportation planning process, the Grand Valley Metro Council (GVMC) completed the transportation conformity process for GVMC’s 2050 Metropolitan Transportation Plan (MTP) and WestPlan’s 2050 Long-Range Transportation Plan (LRTP), as well as the Macatawa Area Coordinating Council’s (MACC’s) 2050 LRTP and all three FY2023-2026 Transportation Improvement Programs (TIPs) and relevant portions of the State Transportation Improvement Plan (STIP).

The results of the conformity process are located in the Transportation Conformity Determination Report for the 1997 Ozone NAAQS document. This report documents that the GVMC 2050 MTP, WestPlan 2050 LRTP, the MACC 2050 LRTP, and all three 2023-2026 TIPs, and relevant portions of the State Transportation Improvement Plan (STIP), meet the federal transportation conformity requirements in 40 CFR Part 93.

This report is subject to public comment. GVMC’s public comment period for the report is from Friday, March 22, 2024 - Monday, April 22, 2024, which coincides with the public comment period for the 2050 MTP. On Wednesday, May 15, 2024, at the regularly scheduled Policy Committee meeting, the Policy Committee will be asked to make a formal conformity determination through a resolution. Our committee meeting schedule and agendas are located here.

Air Quality Conformity Report for the draft FY2023-2026 Transportation Improvement Plan (TIP)

As part of its transportation planning process, the Grand Valley Metro Council (GVMC), the West Michigan Metropolitan Transportation Planning Program (WestPlan), Macatawa Area Coordinating Council (MACC), and relevant portions of the State Transportation Improvement Plan (STIP) completed the transportation conformity process for the new 2023-2026 Transportation Improvement Programs (TIPs) as well as the GVMC 2045 Metropolitan Transportation Plan (MTP), and WestPlan 2045 Long-Range Transportation Plan (LRTP), and the MACC 2045 LRTP.

The results of the conformity process are located in the Transportation Conformity Determination Report for the 1997 Ozone NAAQS. This report documents that the GVMC 2045 MTP, WestPlan 2045 LRTP, the MACC 2045 LRTP, and all three associated 2023-2026 TIPs, as well as the STIP in Ottawa County, meet the federal transportation conformity requirements in 40 CFR Part 93. This conformity determination was completed consistent with CAA requirements, existing associated regulations at 40 CFR Parts 51.390 and 93, and the South Coast II decision, according to EPA’s Transportation Conformity Guidance for the South Coast II Court Decision issued on Nov. 29, 2018.

This report was subject to public comment. GVMC’s public comment period for the document ran from May 2 to May 16, 2022. No comments were received. On Wednesday, May 18, at the regularly scheduled Policy Committee meeting, the Policy Committee made a formal conformity determination through a resolution. Our committee meeting schedule and agendas are located here.

Air Quality Conformity Report for 2045 Metropolitan Transportation Plan (MTP)

As part of its transportation planning process, the Grand Valley Metro Council (GVMC) and the West Michigan Metropolitan Transportation Planning Program (WestPlan) completed the transportation conformity process for the draft GVMC 2045 Metropolitan Transportation Plan (MTP), the WestPlan 2045 Long-Range Transportation Plan (LRTP), as well as the Macatawa Area Coordinating Council (MACC) 2045 (LRTP), all three FY2020-2023 Transportation Improvement Programs (TIPs), and relevant portions of the State Transportation Improvement Plan (STIP).

The results of the conformity process are located in the Transportation Conformity Determination Report for the 1997 Ozone NAAQS document. This report documents that the GVMC 2045 MTP, WestPlan 2045 LRTP, the MACC 2045 LRTP, and all three associated 2020-2023 TIPs, as well as the STIP in Ottawa and Kent Counties, meet the federal transportation conformity requirements in 40 CFR Part 93.

This report was subject to public comment. GVMC’s public comment period for the document ran from Monday, January 13 – Monday, February 3, 2020. No comments were received. On Wednesday, April 15, 2020, at the regularly scheduled Policy Committee meeting, the Policy Committee made a formal conformity determination through a resolution. Our committee meeting schedule and agendas are located here.

Air Quality Conformity Analysis for FY2020-2023 TIP

In March of 2019, MDOT conducted an air quality conformity analysis for Kent and Ottawa Counties based on the 1997 ozone standard. Projects in the 2040 LRTPs have not changed since the previous air quality conformity analysis conducted in January 2019 and are included in the modeling but not in the project lists. Projects evaluated for this analysis include:

  • GVMC’s 2020-2023 TIP

  • WestPlan’s  2020-2023 TIP projects in Ottawa County

  • MACC’s 2020-2023 TIP projects in Ottawa County

  • The State Transportation Improvement Program (STIP) in Kent and Ottawa Counties

The staff of the GVMC, WestPlan, and MACC find that the LRTPs and TIPs conform to the SIP for the 1997 ozone standard based on the results of the conformity analysis.

Conformity is demonstrated when the analysis-year emissions are equal to or less than the SIP budget (see below). The emissions results for the analysis years show that the volatile organic compounds (VOC) and nitrogen oxides (NOx) emissions are lower than the SIP budgets; thus, conformity for the ozone standard is demonstrated.

New TIP table.png

Interagency Consultation

Consultation with federal, state, and local transportation authorities is conducted through the Michigan Transportation Conformity Interagency Workgroup (MITC-IAWG). Issues discussed include evaluating and choosing emission models and methods, determining regionally significant project definition, procedures for future MITC-IAWG meetings, and rules for reviewing projects.

For more information, please see the project lists from the FY2017-2020 TIP, FY2020-2023 TIP, and 2040 MTP (GVMC’s Long Range Transportation Plan), which have been evaluated by the MITC-IAWG Committee. Please note that the project lists include whether projects are air quality exempt or non-exempt.  

The MITC-IAWG Committee evaluates all TIP and LRTP amendments to determine if projects are air quality exempt, meaning they do not have to be included in a conformity analysis, or if a project is non-exempt, meaning it has to be included in a conformity analysis. The GVMC Technical and Policy Committees also approve TIP and LRTP amendments at their regularly scheduled meetings. To view Technical and Policy Committee agendas, please visit our Committee Meetings and Agendas page.    

Additional Information

Please visit the West Michigan Clean Air Coalition’s web page for detailed information about the history of air quality in West Michigan.

For more information about the TIP, please click here.

For more information about the MTP, please click here.

If you have questions about the air quality conformity document, please email Andrea Faber or call 616.776.7603.