California Air Resources Board

The Congestion Mitigation and Air Quality (CMAQ) Program (23 U.S.C. 149) was established by the 1991 Federal Intermodal Surface Transportation Efficiency Act (ISTEA) and was most recently reauthorized with the passage of the Bipartisan Infrastructure Law (BIL) in 2021. CMAQ 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).

Under the CMAQ program, State Departments of Transportation (DOTs) and Metropolitan Planning Organizations (MPOs) are encouraged to consult with State and local air quality agencies in nonattainment and maintenance areas on the estimated emission reductions from proposed congestion mitigation and air quality improvement programs and projects.

Cost Effectiveness Analysis

Quantification Methodologies

The Methods to Find the Cost-Effectiveness of Funding Air Quality Projects document includes methods and examples for evaluating the emission reductions and cost-effectiveness of CMAQ projects and Assembly Bill (AB) 2766 Motor Vehicle (MV) Fees projects.

Automated Tool

The following tool enables staff and decision-makers to quantify the cost-effectiveness of proposed projects in terms of cost per pound (or ton) of pollutants reduced. This tool is used to evaluate projects and to report on both the CMAQ and the Motor Vehicle Registration Fee Program.

This automated Access database program allows users to quantify emissions benefits for the following project categories: cleaner on- and off-road vehicle purchases and re-powers; cleaner street sweepers; new bus service operations; vanpool and shuttle service; traffic signal coordination; bicycle facilities; telecommute programs; ridesharing, pedestrian facilities, or any other project that reduces auto trips or auto trip lengths. 

• Automated Cost-effectiveness Calculation Tool  (MS Access database download)

Note that, in order to use the MS Access database (.mdb) file, after downloading the file you may need to open the file properties and check the box labeled “unblock.”

Emission Factor Tables

The latest emission factor tables below are to be applied in the Automated Cost-effectiveness Calculation Tool.

• Emission Factors Tables (October 2024)

Additional Resources

The Federal Highway Administration (FHWA), in cooperation with the Federal Transit Administration, has also developed cost-effectiveness analysis methods for various types of CMAQ projects. Staff may also apply these analysis methods developed by FHWA to estimate the cost-effectiveness of CMAQ projects when appropriate:

FHWA CMAQ Emissions Calculator Toolkit

CMAQ Project Type and Cost Effectiveness Tables Summary

If you have any questions on the CMAQ program, please send an email to CMAQ@arb.ca.gov