For several CAFE rulemakings, NHTSA has made significant use of results produced by the CAFE Compliance and Effects Model (commonly referred to as 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.

Other tasks the model can perform include calculating the costs, effects, and benefits of technologies that could be added in response to a given CAFE standard; fitting a mathematical function forming the basis for an attribute-based CAFE standard; evaluating many potential levels of stringency sequentially; and performing uncertainty analysis (i.e., Monte Carlo simulation).

The Volpe Model, its system documentation, source code, and input files can be downloaded via the links below:

Model Years 2011 and prior
Model software
System documentation
Source code
Sample input files

Note 1: These files are self-extracting archives of many text and Excel files, and were compressed using 7 ZIP, which is available at


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