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What is CMAQ?

The Congestion Mitigation and Air Quality (CMAQ) Improvement program provides a flexible funding source for State and local governments to support transportation projects and programs that help improve air quality and reduce traffic congestion. This funding is intended for areas not meeting the National Ambient Air Quality Standards (NAAQS)-nonattainment areas-and areas that previously did not meet the standards, but now do-maintenance areas.

A wide range of transportation projects and programs are eligible, including traffic flow improvements, bicycle and pedestrian pathways, and idle reduction technology, among others. The Federal Highway Administration and the Federal Transit Administration, in consultation with the U.S. Environmental Protection Agency (EPA), jointly administer the program.

The CMAQ program was established under the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, and reauthorized under the Transportation Equity Act for the 21st Century (TEA-21) in 1997. Since its inception, the CMAQ program has provided more than $13 billion in funding for more than 16,000 projects across the country.

In August 2005, CMAQ was again reauthorized under the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU). This brochure describes the CMAQ program and highlights key elements of the program under SAFETEA-LU, including changes in eligibility requirements.


This chart shows how CMAQ authorization levels have increased since 1992. In 1992, under ISTEA, the CMAQ authorization was 0.86 billion dollars. Ten years later in 2002, under TEA-21, the CMAQ authorization was 1.41 billion dollars. According to the chart, in 2007, the authorization is 1.72 billion dollars. This number will increase to 1.78 billion dollars in 2009. The chart also includes a note that in 2004, the CMAQ program authorization was extended at the same level as 2003.

SAFETEA-LU was enacted in August 2005 to provide funding for the Nation's surface transportation programs through 2009. Representing the largest surface transportation investment in the Nation's history, SAFETEA-LU establishes numerous new transportation programs and reauthorizes many of the programs created under ISTEA and TEA-21.

Broad in scope, SAFETEA-LU addresses the many challenges facing today's transportation system, such as improving safety, reducing traffic congestion, improving efficiency in freight movement, increasing intermodal connectivity, and protecting the environment. SAFETEA-LU also lays the groundwork for addressing future challenges.

How much funding is available through the CMAQ program under SAFETEA-LU?

SAFETEA-LU funds CMAQ at approximately $1.7 billion per year-a 27-percent increase over the average annual CMAQ authorization under TEA-21.

This funding will be augmented by equity bonus funds to ensure that each State's return on its share of contributions to the Highway Trust Fund is at least 90.5 percent in 2005, building toward a minimum 92-percent relative rate of return by 2008.

How are CMAQ funds apportioned under SAFETEA-LU?

Every State receives at least a 0.5-percent minimum apportionment of CMAQ funds. Additional funds are apportioned according to a formula based on a State's population in ozone and carbon monoxide nonattainment and maintenance areas.

SAFETEA-LU modified the weighting factors for carbon monoxide and ozone areas. Additional weight is given to counties that are nonattainment or maintenance areas for both the carbon monoxide and ozone NAAQS. The formula does not account for particulate matter pollution, but CMAQ funds can be used in particulate matter areas.

The Population Weighting Factors under TEA-21 and SAFETEA-LU.
CO or O3 Maintenance .08 1.0
O3 Subpart 1 N/A 1.0
O3 Marginal 1.0 1.0
O3 Moderate 1.1 1.1
O3 Serious 1.2 1.2
O3 Severe 1.3 1.3
O3 Extreme 1.4 1.4
CO Nonattainment 1.0 1.0
CO + O3 Maintenance 1.1 x O3 factor 1.2 x O3 factor
CO + O3 Nonattainment 1.2 x O3 factor 1.2 x O3 factor

To receive CMAQ funding, what is required?

Key CMAQ funding requirements have not changed with SAFETEA-LU. States with nonattainment or maintenance areas must invest their funds in those regions. This includes areas newly-designated as nonattainment under the 8-hour ozone standard and the fine particulate matter standard (PM2.5). States without nonattainment or maintenance areas may use their CMAQ funds for any project or program that is eligible for CMAQ or Surface Transportation Program funding.

All CMAQ projects must come from a conforming transportation plan and Transportation Improvement Program (TIP) in metropolitan areas or State TIP in rural areas. The State transportation department is responsible for distributing the funds. The Federal share for most CMAQ-eligible projects is 80 percent, but State and local officials are encouraged to seek a larger match than required by law in cases such as public-private partnerships. The CMAQ program operates on a reimbursable basis, so funds are not provided until work is completed.

What projects are eligible for CMAQ funds?

CMAQ funds continue to be available for a wide range of transportation projects, including:

SAFETEA-LU highlights several types of projects, including:

Does SAFETEA-LU change the way CMAQ projects are selected and funds are spent?

SAFETEA-LU does not change the way State and local agencies distribute CMAQ funds. However, States and metropolitan planning organizations are encouraged to give priority to projects and programs that finance diesel retrofits and other cost-effective emission-reduction activities, in addition to cost-effective congestion-mitigation activities that provide air quality benefits.

Are there any other provisions of SAFETEA-LU that involve CMAQ?

SAFETEA-LU also requires the U.S. Department of Transportation (DOT), in consultation with EPA, to evaluate and assess a representative sample of CMAQ projects. The goal is to determine the direct and indirect impacts of the projects on air quality and congestion to ensure that the CMAQ program is being effectively implemented. In addition, DOT will continue to maintain and disseminate information from the CMAQ project database, which tracks all CMAQ projects and their impacts.

For more information, please contact:
U.S. Department of Transportation Federal Highway Administration
Office of Natural and Human Environment
400 7th Street, S.W., Room 3240
Washington, D.C. 20590; 202-366-6724


This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for use of the information contained in this document. This report does not constitute a standard, specification or regulation.

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The Federal Highway Administration provides high quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

It all adds up to cleaner air


February 2007

Updated: 9/23/2013
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