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Streamlining the Estimation of Emission Reductions for CMAQ Projects Using Look-Up Tables


The Congestion Mitigation and Air Quality (CMAQ) Program is one in which Federal Highway Administration (FHWA) distributes funds to States to assist in projects and programs that help to reduce vehicle-related emissions in non attainment or maintenance areas. Many types of projects can be considered for CMAQ funding including traffic signal synchronization, ride-sharing programs, and diesel retrofit projects. To obtain CMAQ funds, States must submit an analysis describing the air quality improvement benefits that the project or program will achieve. Analyses submitted in the past to justify a particular project or program have varied widely from a simple qualitative description of the estimated emission reduction benefit to more complex project-specific quantitative analyses. As the time and cost for conducting such analyses can be significant, state departments of transportation (DOTs) and other project sponsors would benefit from simplified procedures, including specifically the use of lookup tables for typical project types, that would serve to significantly reduce the time and cost for analyses for state DOTs while also helping to improve the consistency and accuracy of the estimated emission reductions for FHWA. For example, in its simplest form, tables of estimated emission reductions by project type and year could be developed. Then, in lieu of project-specific modeling, the state DOT or other project sponsor would only need to look up the estimated emission reduction in the table for the given project type and year, and in their documentation simply reference the lookup table as the source.

For reference, the new programmatic eligibility option provided in Moving Ahead for Progress in the 21st Century Act (MAP-21) and specified by FHWA in CMAQ guidance may be one option for implementing the proposed new lookup tables.


Given federal and state priorities for streamlining the project-development process, streamline the determination of emission reductions for CMAQ projects through the development and implementation of lookup tables and otherwise simplified procedures. The intent is to reduce the time and cost to state DOTs and other project sponsors for CMAQ analyses and at the same time improve the accuracy, quality control, and utility of the estimated emission reductions to FHWA.


Potential tasks are outlined below. In general, panel review and approval is needed with each task.

  1. Working closely with the project panel and FHWA, review and refine the project scope of work to best complement any related initiatives that FHWA may have in development. For example, the scope of work for this project may focus on smaller projects that are more appropriate candidates for the use of look up tables, while FHWA may focus on developing simplified procedures for projects of larger scope and/or complexity.
  2. If not already specified in the revised scope of work, identify project and program types that would be appropriate candidates for the use of lookup tables for emission reductions. This is expected to involve a very brief review of project and program types specified in CMAQ guidance and associated typical emission reduction methodologies. Develop a preliminary set of emission reduction look-up tables that are designed to be applied to the targeted projects and programs identified in the previous task. The analyses should be based on the latest official version of the EPA MOVES model. Separate sets of tables may be needed for different regions of the country to better reflect regional differences in modeling inputs. Other approaches that have been used and can be confidently defended should also be consulted and considered. Note the lookup tables should be designed to complement and not unduly overlap with the “tool kit’ that is currently being developed by the Volpe Center for FHWA. The Volpe tool kit is focused on projects of a larger scope that would require a simplified set of modeling inputs (versus a simple lookup table). It is being completed in stages, so at this time may not contain examples of analyses for all projects and programs.
  3. Prepare a draft report for the project. Document the emission reduction analysis methodology and how the tables may be updated in the future. Provide examples of how the lookup tables are to be used.

  4. Following approval by the project panel of draft tables and report, prepare a final set of tables and report.

Sponsoring Committee:AMS10, Air Quality and Greenhouse Gas Mitigation
Research Period:12 - 24 months
Source Info:Christopher Voigt,
Virginia Department of Transportation

Kevin Black,
Federal Highway Administration (FHWA)
Date Posted:09/19/2016
Date Modified:09/28/2016
Index Terms:Maintenance, Traffic signals, Ridesharing, Diesel engines, Air quality management, Pollutants, Congestion Mitigation and Air Quality Improvement Program, Vehicles,
Cosponsoring Committees: 
Planning and Forecasting

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