Each time NHTSA proposes or finalizes new CAFE standards, the agency must consider options and estimate the impacts of each option.  For all CAFE rulemakings since 2003, NHTSA has made significant use of results produced by the CAFE Compliance and Effects Model (commonly referred to as “the CAFE model” or “the Volpe model”), developed by DOT’s Volpe National Transportation Systems Center to support NHTSA’s CAFE rulemakings. NHTSA uses the model as a tool to estimate how manufacturers could attempt to comply with a given CAFE standard by adding technology to anticipated future vehicle fleets, and to estimate impacts of that additional technology on fuel consumption, greenhouse gas emissions, and economic costs and benefits to vehicle owners and society.  NHTSA also uses the model to evaluate the sensitivity of these estimated outcomes to key analytical inputs (e.g., fuel prices), and to perform probabilistic uncertainty analysis.

• Watch: Video Introduction to the CAFE Model 
• Graphic: CAFE Model Inputs and Outputs

Available Versions and Analyses

NHTSA has continually improved the CAFE model, and with every new CAFE rulemaking since 2008, NHTSA releases the version used, its source code, and the inputs and outputs that underlay the rulemaking analysis. Here's a look at major ways the model has evolved over time.

Outlook

NHTSA and the Volpe Center are continuing to develop the model to support future fuel-economy-related analyses. New versions of the model will be released along with future NHTSA analyses.

Contact: CAFEModel@dot.gov

The model, its system documentation, source code, and input files can be downloaded from NHTSA's ftp server via the links below (listed from newest to oldest).