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Intelligent Transportation Systems (ITS)

What is CMAQ?

The Congestion Mitigation and Air Quality (CMAQ) Improvement Program provides a flexible funding source for state and local governments to fund transportation projects and programs to help meet the requirements of the Clean Air Act (CAA) and its amendments. CMAQ money supports transportation projects that reduce mobile source emissions in areas designated by the U.S. Environmental Protection Agency (EPA) as in nonattainment or maintenance of national ambient air quality standards. Eligible activities include transit improvements, ITS or traffice flow improvements, and public fleet conversions to cleaner fuels, among others.

What are the Key CMAQ Funding Requirements?

CMAQ funds must be invested in a state's nonattainment or maintenance area(s). The money must be spent on projects that reduce ozone (O3) precursors – volatile organic compounds (VOCs) and nitrogen oxides(NOx) – carbon monoxide (CO), or particulate matter (PM) from transportation sources. States without nonattainment or maintenance areas may use their CMAQ funds for projects eligible under the CMAQ or Surface Transportation Programs anywhere in the state. All CMAQ projects must come from a transportation plan and Transportation Improvement Program (TIP). The state transportation department is responsible for distributing CMAQ funds.

All projects must conform to established CMAQ guidance. The federal share for most CMAQ-eligible projects is 80 percent. The CMAQ program operates on a reimbursable basis, so funds are not provided until work is completed.

CMAQ, Air Quality, and ITS: What's the Connection?

Intelligent Transportations Systems (ITS) are a combination of computer and communication technologies, as well as institutional partnerships, which make existing transportation systems operate more efficiently and safely.

ITS technology includes:

A map of the U.S. showing the deployment status of 511 systems

One of the ARTIMIS variable message signs.

One of the ARTIMIS variable message signs.

These strategies reduce emissions by promoting efficient traffic movement. ITS projects improve traffic flow characteristics, such as speed; improved traffice flow can reduce emissions rates in many situations.

Examples of Successful ITS Projects

The Advanced Regional Traffic Interactive Management and Information System (ARTIMIS) is a transportation system management project designed to improve traffic flow. It was put in place by the Ohio-Kentucky-Indiana (OKI) Council of Governments to monitor and control traffic on 88 miles of regional freeways at a total cost of $57 million, of which $41 million were CMAQ funds. The OKI estimates emissions reductions of 186 kg/day of VOC.

Arterial Street Signal Interconnect, Philadelphia, PA, is an interconnection of traffic signals along arterials with high transit use implemented to improve traffic flow and to enhance transit quality. The total annual project cost was $214,033, of which $171,227 were CMAQ funds. Estimated emissions reductions were 52 kg/day, VOC and 5.7 kg/day NOx.

The Georgia NAVIGATOR is an Advanced Transportation Management System that monitors and manages traffic conditions on 90 miles of interstate highway in the Atlanta metropolitan area. The system was developed at a total cost of $140 million, of which $54 million were CMAQ funds. The Georgia DOT estimates emissions reduction benefits of 614 kg/day VOC and 578 kg/day NOx.

A variable message sign displaying travel times.

The variable message sign displays travel times.Photograph courtesy of Wisconsin DOT.

Atlanta, Georgia's NAVIGATOR monitoring and managing traffic along an interstate

Atlanta, Georgia.

A Utah Department of Public Safety staff member operates a regional traffic operations system.

A Utah Department of Public Safety staff member operates a regional traffic operations system.

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, DC 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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It all adds up to cleaner air


October 2005

Updated: 7/6/2011
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