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Long Range Planning Division
Research & Policy Office

Research & Policy Office
James K. Polk Building, Suite 900
505 Deaderick Street
Nashville, Tennessee 37243-0344
Phone: 615.253.6301
Fax: 615.532.8451

Congestion Management and Air Quality Program Management

The federal Congestion Mitigation and Air Quality Improvement (CMAQ) program provides dedicated federal funding to state Departments of Transportation for projects that improve air quality and reduce congestion. The CMAQ program improves air quality by funding transportation projects and programs that reduce air emissions from cars, trucks and buses (mobile sources) in air quality nonattainment and maintenance areas, which are the only areas eligible for CMAQ funding.

Areas that do not meet National Ambient Air Quality Standards (NAAQS) for selected air pollutants (carbon monoxide, ozone, and particulate matter) are called nonattainment areas. These areas are formally designated under the federal Clean Air Act by the U.S. Environmental Protection Agency (EPA) as having air pollution levels that are at times unhealthy for human beings.

When air quality in a nonattainment area improves and meets these federal air quality health standards and is no longer designated as nonattainment, it becomes a maintenance area. Maintenance areas must continue to take actions to ensure that measured air quality does not become worse and the area continues to meet the required NAAQS levels.

The following counties are eligible for CMAQ projects in Tennessee: Anderson, Blount, Cocke (partial county), Davidson, Hamilton, Jefferson, Knox, Loudon, Montgomery, Roane (partial county), Rutherford, Sevier, Shelby, Sumner, Williamson and Wilson.

Congress authorizes and appropriates funding for the CMAQ program, and CMAQ funds are then distributed by the Federal Highway Administration (FHWA) to state departments of transportation based on populations living in air quality nonattainment and maintenance areas. The distribution formula takes into account the severity of regional air quality problems.

Projects Eligible for CMAQ Funding

State Departments of Transportation (DOTs), local governments and MPOs may use CMAQ funds for a variety of transportation-related measures and programs. Project types typically considered eligible for CMAQ funding include the following:

  • Retrofit control equipment for diesel engines (e.g., diesel retrofits, engine repowers)
  • Idling reduction projects
  • Transportation Control Measures (TCMs) that produce air quality benefits
  • Public-Private Partnerships to implement projects that reduce emissions (must have a public agency sponsor)
  • Alternative Fuels Infrastructure
  • Traffic Flow Improvements
  • Transit Projects
  • Bicycle and Pedestrian Facilities and Programs (also eligible for Transportation Alternatives funding)
  • Travel Demand Management (TDM) Programs
  • Education and Outreach Programs
  • Rideshare Activities
  • Transit Fare Subsidy Programs for Air Quality Action Days
  • Intermodal Freight Projects
  • Vehicle Inspection (I/M) Programs
  • Intelligent Transportation Systems (ITS)
  • Experimental Pilot Projects

Eligible highway projects include traffic flow improvements, such as traffic signal control systems, incident management programs, high-occupancy vehicle (HOV) lanes and truck climbing lanes that do not increase capacity. Projects that increase highway capacity are not eligible for CMAQ funding as they lead to increased vehicle emissions. CMAQ funds may be used for projects that reduce congestion as long as those projects achieve reductions in air emissions. Highway rehabilitation and maintenance activities generally show no potential to reduce vehicle emissions and are not eligible for CMAQ funding.

Match Requirements

For most projects, CMAQ funding pays a maximum of 80 percent of eligible project costs. A minimum match of 20 percent nonfederal funds is required for those projects.  Project sponsors (e.g., local governments or private sector partners) are responsible for paying the 20 percent match. A small portion of CMAQ projects, such as carpool and vanpool projects, qualify for 100 percent funding.

CMAQ in Tennessee

State DOTs use a range of approaches to developing and implementing CMAQ projects. TDOT selects CMAQ projects through a competitive project proposal process. TDOT develops and publishes project evaluation criteria and assigns numerical scores to each criterion. These numerical scores vary depending on the criterion. Proposals that better address each criterion are awarded higher scores.

Project sponsors (e.g., local governments or nonprofit organizations) prepare project proposals, including air emission reduction analyses, and submit them to the respective Metropolitan Planning Organization (MPO) that includes a nonattainment/maintenance county within its boundaries. The MPO submits a package of proposals from that region to TDOT. TDOT reviews, evaluates and scores the proposals that are received. Based on that review, staff recommends that selected projects be funded. The Commissioner reviews those recommendations and makes the final selection of projects for funding. The next request for proposals will be published in late 2013 in preparation for the new CMAQ funding expected in October 2014, the beginning of federal fiscal year 2015.

All CMAQ projects must be included in TIPs developed by MPOs or the statewide transportation improvement program (STIP) developed by TDOT. All CMAQ projects must also comply with National Environmental Policy Act (NEPA) requirements.

MAP-21 and CMAQ

In July 2012, Congress passed the Moving Ahead for Progress in the 21st Century Act (MAP-21) and reauthorized the CMAQ program for federal fiscal years 2013 and 2014. While project eligibility remains basically the same, the legislation places considerable emphasis on diesel engine retrofits and other efforts that underscore a new priority on reducing fine particle pollution (PM 2.5).

Under MAP-21, states, including Tennessee, with PM 2.5 nonattainment areas must use a portion of its CMAQ funds to address PM 2.5 emissions. Eligible projects to mitigate PM 2.5 include diesel retrofits. Other project categories identified as priorities for CMAQ funding under MAP-21 include transit operating assistance and facilities serving electric or natural gas-fueled vehicles.

The CMAQ program also has new performance-based features. The Secretary of Transportation will establish measures for states to assess traffic congestion and on-road mobile source emissions. Each Metropolitan Planning Organization (MPO) with a transportation management area of more than one million in population representing a nonattainment or maintenance area is required to develop and update biennially a performance plan to achieve air quality and congestion reduction targets. In Tennessee, that will include the Nashville Area and Memphis MPOs. A CMAQ outcomes assessment study for the program is also required.

Legislative Authorizations

Jointly administered by FHWA and the Federal Transit Administration (FTA), the CMAQ program was established in 1991 as part of the Intermodal Surface Transportation Efficiency Act (ISTEA). Continuation of the program was reauthorized by the Transportation Equity Act for the 21st Century (TEA-21) in June 1998, by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) in August 2005 and, most recently, by the Moving Ahead for Progress in the 21st Century Act (MAP-21) in July 2012.

For more information, please contact Alan.Jones@tn.gov