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Public Transportation

What is CMAQ?

Note: This information was archived in September 2013. For current information, see

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, travel demand management strategies, traffic 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.

train station

How Can Public Transportation and Transit Projects Benefit from CMAQ Funds?

CMAQ funds may be used to support the use of public transportation. There are three broad categories of transit projects or programs that are eligible for funding: provision of new transit service, service or system expansion, and financial incentives to use existing transit services.

Service or System Expansion: Service expansion strives to attract new users, typically by providing new transit facilities or additional transit vehicles. Improving intermodal connections in our major urban areas has been a focus since these projects are generally eligible for CMAQ funding provided that they reduce overall emissions. Improved public transit is one of the Transportation Control Measures (TCMs) identified in Section 108(f)(1)(A) of the CAA.

However, not all transit improvements are eligible under the CMAQ program. The general guideline for determining eligibility is whether an increase in transit riders can reasonably be expected to result from the project. As with all CMAQ-funded projects, this must be supported by a quantified estimate of the emissions reductions resulting from the project.

New Transit Service: The start-up of new transit service, for example, new express bus routes or new shuttle service linking major activity centers, is supported under the CMAQ program to tap new markets for transit. Although CMAQ cannot be a permanent source of funding for transit service, the goal is to encourage experimentation to determine whether new services are viable.

Operating Assistance: There are several general conditions that must be met in order for any type of operating assistance to be eligible under the CMAQ program. Operating assistance includes all costs related to ongoing provision of new transportation services including, but not limited to, labor, administrative costs and maintenance. Operating assistance is limited to new transit services and new or expanded transportation demand management strategies for a maximum of three years.

A natural gas bus.

New Vehicles: Acquisition of new transit vehicles?bus, rail, van?to expand the fleet or replace existing vehicles is also eligible. However, diesel-powered replacement vehicles will have minimal impact on attaining the ozone, PM, and CO standards. For these projects in particular, emissions effects must be documented so they can be compared with other CMAQ proposals to allow informed decisions on the best use of available funds. Alternative fuel vehicles are eligible for CMAQ funds, assuming they have a positive impact on air quality.

Fare Subsidies: Financial incentive strategies encourage transit use, and include innovative fare policies as part of an overall effort to reduce exceedances of the air quality standards. Under specific conditions, CMAQ may be used to offset the cost of offering reduced or free transit fares. Subsidies can be provided when the reduced fare is an element of an area-wide strategy for reducing emissions during peak periods of ozone pollution. Examples include "Ozone-Action" programs designed to avoid exceedances when ozone concentrations are high, and are bolstered by more permanent measures that discourage single occupant driving.

Why Are Highway and Transit Maintenance and Reconstruction Projects Not Eligible for CMAQ Funds?

CMAQ projects must have air quality benefits. Routine maintenance and rehabilitation of existing facilities are ineligible for CMAQ funding because they only maintain existing ambient air quality. Ineligible projects include Replacing track or other equipment, reconstructing bridges, stations, and other facilities; repaving or repairing roads; and providing general operating supplies.

Examples of Successful Public Transportation Projects

An electric trolley

Commuter Rail Coaches: New, higher capacity coaches were purchased for Maryland's commuter rail service in the Washington/Baltimore region. The total project cost was $7,236,659, of which $290,111 were CMAQ fundes. Estimated emissions reduction were 76 kg/day VOC, and 255 kg/day NOx.

Houston Clean Air Action Program/ Transit Subsidy: A reduced transit fare program was offered in August when ozone readings typically have been highest. CMAQ funds were $2,625,000 of the $3,500,000 total program cost. Estimated emissions reduction were 80.4 kg/day VOC, and 95.2 kg/day NOx.

Lake Cook Shuttle Bug: An employer-sponsored transit shuttle service operated between a commuter rail stop and a business park in Chicago's suburbs. CMAQ funds were $312,000 of the total project cost of $390,000. Estimated emissions reductions were 17.6 kg/day VOC.

New York City Transit 63rd St - Queens Blvd Connection: Construction of a subway link to facilitate travel between Queens and Manhattan. The project alleviated congestion on the jammed E and F lines running through Queens and resulted in approximately 31 hours per year in savings for the average Queens rider on the E, F, & R lines. The total project cost was $645 million, of which $44 million was CMAQ funds. Estimated emissions reductions were 91 kg/day VOC, 36 kg/day NOx, and 645 kg/day CO.

A New York city subway map

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

For more information on mass transit systems, please visit the FTA Web site at:


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: 1/31/2017
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