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A Sampling of Emissions Analysis Techniques for Transportation Control Measures


Emissions Analysis Techniques for TCMs


Forecasting Approaches

Selecting a Method

Descriptions of Available Methods

Key Inputs and Outputs for Each Method


* General Resources
* Other Emissions Estimation Methodologies
* Information on CMAQ/TCM Strategy Effectiveness

List of Acronyms

General Resources

FHWA information and guidance related to air quality and the CMAQ program is available through the Office of Natural Environment.

EPA's Transportation Air Quality (TRAQ) Center contains data, models, and reports to assist in quantifying the emissions benefits of transportation control measures. TRAQ is maintained by the EPA Office of Transportation and Air Quality.

The Center for Urban Transportation Research at the University of South Florida maintains a web site of "Products and Services Available to Assist the TDM and Telework Professional." Internet:


Other Emissions Estimation Methodologies

California Air Resources Board. "Evaluation of Selected Projects Funded by Motor Vehicle Registration Fees." Sacramento, CA (1995).

Estimates the emissions benefits of specific projects including alternative fuel vehicles, electric vehicles, vehicle scrappage, traffic signal timing, shuttle services, employer trip reduction, telecommunications, bicycle use and infrastructure, public education, and smoking vehicle abatement. Assumptions and calculation methods are clearly documented.

Federal Highway Administration. "Off-Model Air Quality Analysis: A Compendium of Practice." FHWA Southern Resource Center (August 1999). Contact Andrew Edwards, (404) 562-3673.

Includes examples of emission reduction calculations from programs throughout the southeastern U.S. Examples cover a variety of strategies such as traffic flow improvements, HOV, transit, vanpool, pedestrian/bicycle, incident management, and public education.

North Jersey Transportation Planning Authority. "TCM Quick Response Handbook: Tools for Local Planners." Prepared by Sarah Siwek and Associates and Apogee Research, Inc.

Contains examples of calculation approaches and worksheets for estimating the emissions impacts of TCM measures including activity center-based trip reduction, bicycling improvements, incident management and information advisory systems, land use measures, parking controls, parking pricing measures, traffic flow improvements, transit pricing programs, and transit improvement programs.

U.S. Environmental Protection Agency, Office of Policy, Planning, and Evaluation. Guidance on the Use of Market Mechanisms to Reduce Transportation Emissions (March 1998). Prepared by Apogee Research, Inc., et al. Internet:

Discusses modeling approaches to address parking fees, VMT fees, and other cost-based TCMs. Methods include the STEP model (a microsimulation approach to travel modeling), the logit mode choice model, and the Post Processor for Air Quality (PPAQ) developed by Garmen Associates for applying MOBILE emission factors to travel model output.

Federal Highway Administration, Turner-Fairbanks Highway Research Center. Guidebook on Methods to Estimate Non-Motorized Travel. Prepared by Cambridge Systematics, Inc., and Bicycle Federation of America. Publication No. FHWA-RD-98-165 (July 1999). Internet:

Reviews available methods to forecast changes in bicycle and pedestrian travel as a result of facility improvements or policies.


Information on CMAQ/TCM Strategy Effectiveness

National Association of Regional Councils. Costs and Effectiveness of Transportation Control Measures (TCMs): A Review and Analysis of the Literature. Prepared by Apogee Research, Inc. (1994).

Federal Highway Administration. Transportation and Global Climate Change: A Review and Analysis of the Literature. Prepared by Hagler-Bailly, Inc. Publication No. DOT-T-97-03 (1998).

Institute of Transportation Engineers. A Toolbox for Alleviating Traffic Congestion and Enhancing Mobility. Prepared by Michael D. Meyer for Federal Highway Administration (1997). Internet:

Transit Cooperative Research Program. Traveler Response to Transportation System Changes Handbook, 3rd Edition. Prepared by Richard Pratt. TCRP Project B-12, TCRP Web Document 12 (2000). Internet:


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