Transportation and Climate Change Clearinghouse
Congestion Mitigation and Air Quality (CMAQ) Improvement Program
U.S. DOT Center for Climate Change
Reauthorized in 1998 under the Transportation Equity Act for the 21st Century (TEA-21) and again as part of the Safe, Accountable, Flexible, Efficient, Transportation Equity Act: A Legacy for Users (SAFETEA-LU) in 2005, the CMAQ program provides over $8.1 billion dollars in funds to State DOTs, MPOs, and transit agencies to invest in projects that reduce emissions from transportation-related sources. Since 1991, the program has provided funding to over 16,000 projects.
The Congestion Mitigation and Air Quality Improvement (CMAQ) Program provides funds to States for transportation projects designed to reduce traffic congestion and improve air quality, particularly in areas of the country that do not attain national air quality standards. Created by the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, the program was reauthorized under the Transportation Equity Act for the 21st Century (TEA-21) in 1997 and again as part of the Safe, Accountable, Flexible, Efficient, Transportation Equity Act: A Legacy for Users (SAFETEA-LU) in 2005. From its beginning, the CMAQ program has been a key funding mechanism for helping urban areas meet air quality goals and supporting investments that encourage alternatives to driving alone and improve traffic flow.
The variety of transportation projects funded through the CMAQ program since its inception reflect both the diversity of local transportation systems and the targeted air quality needs of States and regions. The program has been a key mechanism for supporting investments that encourage alternatives to driving alone, improve traffic flow, and help urban areas meet air quality goals. Since 1991, the program has provided funding to over 16,000 projects and has provided $22.7 billion in funding to States, metropolitan planning organizations (MPOs), and transit agencies to invest in projects that reduce criteria air pollutants regulated from transportation-related sources.
Relationship to Climate Change
Transportation energy use contributes to increased greenhouse gas concentrations in the atmosphere. Emissions of most air pollutants from transportation have declined, but emissions of carbon dioxide (CO2) - the major greenhouse gas - are on the rise. Transportation accounts for about a third of CO2 emissions in the U.S., and transportation emissions are among the fastest-rising among all emitting sectors.
The main goal of the CMAQ program is to fund transportation projects that reduce regulated emissions associated with carbon monoxide, ozone and particulate matter pollution in nonattainment and maintenance areas, often through congestion mitigation techniques. In addition to reducing regulated emissions, congestion relief can reduce travel delays, engine idle time and unproductive fuel consumption. So even though reducing greenhouse gas emissions is not a goal of the CMAQ program, such reductions may be achieved as an ancillary benefit. Lane mileage has increased slowly while highway travel has increased rapidly, resulting in a relatively static surface transportation system which is causing increased congestion. Also, while emissions are generally being reduced nationally, most metropolitan areas are experiencing increases in congestion. Reducing congestion is an important goal for all metropolitan areas and CMAQ plays a role in both large and small metropolitan areas in slowing the growth of congestion, reducing emissions, and maintaining economically viable and mobile communities.
The Secretary of Transportation is required to establish and implement the Congestion Mitigation and Air Quality (CMAQ) Improvement Program. The authority to administer the program has been delegated by the Secretary to the Administrators of the Federal Highway Administration (FHWA) and the Federal Transit Administration (FTA). Their responsibilities under the CMAQ program include:
- Making annual apportionments to the States based on the severity of the pollution within each state's borders and the population affected;
- Determining project eligibility;
- Issuing guidance and information on the program, including procedural rules and best practices to encourage the most effective uses of CMAQ
- DOT-FHWA Office of Natural Environment Air Quality Page
- DOT-FHWA CMAQ Page
- FHWA Legislation, Regulations, and Guidelines