California Department of Transportation

Congestion Mitigation and Air Quality (CMAQ) Improvement Program


The Congestion Mitigation and Air Quality (CMAQ) Improvement Program was established by the 1991 Federal Intermodal Surface Transportation Efficiency Act (ISTEA) reauthorized with the passage of Transportation Equity Act for the 21st Century (TEA-21), and superseded by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU). Funds are directed to transportation projects and programs which contribute to the attainment or maintenance of National Ambient Air Quality Standards (NAAQS) in nonattainment or air quality maintenance areas for ozone, carbon monoxide, or particulate matter (PM) under provisions in the Clean Air Act (Title 42, United States Code).

FHWA CMAQ Program Guidance

CMAQ Program under SAFETEA-LU - Final Program Guidance (10/2008)

I. Introduction
II. Program Purpose
III. Authorization Levels under the SAFETEA-LU
IV. Priority for Use of CMAQ Funds
V. Annual Apportionments of CMAQ Funds to States
VI. Geographic Areas Eligible to use CMAQ Funds
VII. Project Eligibility Provisions
VIII. Project Selection Process: General Conditions
IX. Program Administration
X. Appendix 1: 23 U.S.C §149
XI. Appendix 2: 23 U.S.C. §104(b)(2) Apportionment
XII. Appendix 3: Considerations for Diesel Retrofit Projects

Links of CMAQ websites:

Caltrans CMAQ website:

FHWA's CMAQ Information:

FHWA home page:

National Strategy to Reduce Congestion on America's Transportation Network:

U.S. Department of Transportation’s Innovative Finance Program:

FHWA’s Office of Operations: Strategies & Program Areas:

FHWA’s Office of Operations: Value Pricing Pilot Program:

Public Education and Outreach Activities. It All Adds Up to Cleaner Air:

EPA’s National Clean Diesel Campaign:

Annual Reports. CMAQ Tracking System:

California Air Resources Board - Diesel Emission Control Strategies Verification:

EPA’s State & Local Transportation Resources. Vehicle/Equipment Replacement Projects. EPA's retrofit guidance:

Best Workplaces for Commuters:

EPA’s Voluntary Diesel Retrofit Program: Verified Products:

EPA’s Heavy Trucks, Buses and Engines: Engine Certification Information Center:

If you have any questions or comments, please contact the DLA Webmaster.

To report any difficulty experienced in accessing Caltrans programs, services or activities or any discriminations covered under the Americans with Disabilities Act, Section 504 of Rehabilitation Act or the Fair Employment and Housing Act, please contact us at (866)810-6346 Voice; 711 TTY; (916)324-1999. Email:

Page Last Updated: March 22, 2018