Transportation

Air Quality Conformity

Transportation planning in the region is heavily influenced by air quality planning, which like financial constraint, is a federal requirement. Once the financially constrained element of the long-range transportation plan (LRTP), currently called Visualize 2045, is drafted, it is tested to ensure that, the plan's projects collectively contribute to the air quality improvement goals embodied in the Clean Air Act Amendments of 1990. A series of tests are performed with computer models that predict how much air pollution will be generated over the next 25 years by facilities in the plan, and how much the air will be improved by cleaner gasoline standards and many other factors.

If the LRTP is found by the TPB to meet regional air quality goals, federal agencies certify that the plan is "in conformity." In other words, the TPB ensures that the constrained element "conforms" to air quality improvement goals. If the TPB encounters difficulty in meeting conformity - or expects to - it may choose to adopt Transportation Emission Reduction Measures (TERMs), such as ridesharing and telecommuting programs, improved transit and bicycling facilities, clean fuel vehicle programs or other possible actions. This information is documented in an Air Quality Conformity Determination report

Visualize 2050 National Capital Region Transportation Plan
2025 Air Quality Conformity Analysis Update

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Visualize 2050, the National Capital Region Transportation Plan, is the update to Visualize 2045. In 2025, TPB staff completed an Air Qualiy Conformity Analysis of the projects in the draft Visualize 2050 plan. To learn more, view the Visualize 2050 Air Quality Conformity FAQs

Public Comment Opportunity

The draft Air Quality Conformity Analysis Report, along with the Visualize 2050 draft plan, and draft FY 2026-2029 Transportation Improvement Program, is open for public comment October 23-November 21, 2025. Visit visualize2050.org to view the report and for information on how to comment.   

News & Multimedia

  • Orange and Blue Line
    News

    TPB invites comments on the region's long-range transportation plan

    April 1, 2022

    The National Capital Region Transportation Planning Board (TPB) is seeking public comment on Visualize 2045, the long-range transportation plan update for the...

  • arial_dc_john_sonderman_flickr-600
    News

    Air quality conformity, explained

    February 10, 2020

    Have you ever heard us talk about air quality conformity? It’s a bit of transportation jargon that’s incredibly important for our region. But what does it...

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