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The Congestion Mitigation and Air Quality Improvement Program

CMAQ Funding

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

During the initial 1992-1997 CMAQ Program period, a total of $6 billion was available for projects. Basic funding levels for the 1998-2003 TEA-21 program period were increased by 35 percent and are authorized at $8.1 billion. The basic amount of available funding is determined by a formula calculation based on population and EPA's severity classification for ozone and carbon monoxide air pollution (See Figure 7).

These basic authorizations will be augmented, perhaps significantly, from two sources. The first is through the TEA-21 provision that guarantees each State a minimum of 90.5 percent of the funds that are paid into the Highway Trust Fund (HTF). Part of the funds needed to raise a State's total Federal-aid apportionment to this level are added to the CMAQ basic authorization. For example, in 1999 these minimum guarantee funds added $235 million to the basic authorization. The second is through additions, part of which is added to the CMAQ program, which occur when the HTF revenues exceed projections. TEA-21 requires that authorization levels be realigned when this occurs. These funds under the Revenue Aligned Budget Authority are expected to increase CMAQ and other Federal-aid program funds substantially.

TEA-21 funds are apportioned to the State DOTs on an annual basis. Once the funds are apportioned to the State DOT, they are available for four years, and may be "obligated" or dedicated, to specific CMAQ projects.

Figure 7 7
CMAQ Authorization Levels
Under ISTEA Annual Average - $1.0 Billion, Under TEA-21 Annual Average $1.35 Billion

The obligation of funds assures the project sponsor that federal monies are available and will be provided for authorized projects. However, CMAQ funds are only released as reimbursement payments for completed work. Unused funds lapse at the end of the four year availability period, and are no longer available for use by the State.

CMAQ funds require a state or local match. The typical split between federal and project sponsor is 80 percent Federal, 20 percent State and/or local match.

Under certain circumstances a portion of a State's CMAQ funds may be transferred to other Federal-aid programs. This can only occur if the national CMAQ funding level for a given year is greater than $1.35 billion dollars.

If this occurs, a State may transfer up to fifty percent of the surplus actual CMAQ apportionment funds to other Federal-aid projects in the transportation improvement program. However, the transferred funds must still be obligated in nonattainment and maintenance areas. The amount of transferable funds will vary from year-to-year and from State-to-State depending on overall authorization levels. The FHWA is responsible for calculating the amount and tracking the transfer of the eligible CMAQ funds.

Maximizing the Benefits of CMAQ funding

It is important to develop and fund CMAQ projects that will assist an area in reducing transportation-related emissions. Some projects may be more effective and cost-effective than other projects. For some projects, project comparisons can be formulated by calculating an estimate for the amount of emission reductions per dollar spent. This cost-effectiveness analysis assists program managers with the evaluation of dissimilar CMAQ projects (for example, natural gas vehicles and refueling stations versus bike paths). Nevertheless, certain projects are more difficult to analyze. For example, in assessing the impacts of bicycle paths or a ride sharing program assumptions must be made about the number of automobile trips that will be reduced by people choosing these travel options.

Because CMAQ funds are limited compared to needs, planning officials should strive to maximize air quality benefits by allocating resources to the projects that are likely to achieve the greatest reduction in emissions. Consequently, projects that consistently reduce vehicle emissions for all trips may be more beneficial than projects which attempt to alter transportation demand for a particular trip, such as commuting which now constitutes only one-quarter of all trips. A thorough understanding of transportation demand, available resources and local traffic trends should indicate emission reduction strategies that are the most promising for a given geographical area.

The use of travel demand models may assist with the development of travel scenarios and model outputs can assist with estimating the corresponding emissions. Often, these models use many different inputs. FHWA can be contacted for a compilation of techniques that have been used to estimate emissions for a range of transportation projects. Research in this area continues to progress and tools to analyze the impacts of CMAQ funded projects are being continuously refined. While better modeling and improved analysis will almost certainly assist decisionmakers on which projects are estimated to yield better benefits, judgement and thoughtful consideration will also be necessary to select the best projects.

7 Sources: Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991. Transportation Equity Act for the 21st Century (TEA-21) of 1998.

Updated: 9/23/2013
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