In between adoptions of each new plan and TIP, the need for revisions arises, particularly as project development continues. The TPB’s National Capital Region Transportation Plan and Transportation Improvement Program Amendment and Administrative Modification Procedures explain how changes to these documents are made.

TPB SR6-2027 was adopted by the Transportation Planning Board’s Steering Committee on October 2, 2026.

The TPB studies how regionally significant transportation policies, programs, and projects will affect air quality—specifically, ozone season Volatile Organic Compounds (VOC) and Nitrogen Oxides (NOx) emissions.

Air Quality Conformity refers to whether the regional significant projects in the plan collectively meet the air quality goals embodied in the Clean Air Act Amendments of 1990. If the Visualize 2050 plan is found by the TPB to meet regional air quality goals, federal agencies will review and certify that the plan is “in conformity” or meets future regional air quality standards. Following the TPB’s adoption of Visualize 2050 and the Air Quality Conformity Analysis Report, the federal government reviews these documents and determines if they concur with the report’s findings on conformity with the requirements of the 1990 Amendments to the Clean Air Act. This determination is the formal completion of the Visualize 2050 plan development process.

Resolution R3 – Finding that the Visualize 2050 National Capital Region Transportation Plan and the FY 2026-2029 Transportation Improvement Program conform with the requirements of the Clean Air Act Amendments of 1990

Air Quality Conformity Analysis Report of Visualize 2050 and the FY 2026-2029 Transportation Improvement Program

Appendix A: Scope of Work

Appendix B: Project Inputs

Appendix C: Documentation of Data Development Process for Mobile Source Emissions Calculations

Appendix D: Transportation Control Measures (TCMs) Implementation Reports

Appendix E: Interagency Consultations and Public Involvement Process

Appendix F: TPB C-SMMPO Agreement

Additional information: Visualize 2050 Air Quality Conformity FAQs