Corporate Average Fuel Economy

Compliance and Effects Modeling System

The Volpe Model


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.


Available Versions and Analyses

Since 2008, NHTSA has released successive versions of the model, source code, inputs, and outputs underlying analyses supporting proposed and final rules regarding CAFE standards for passenger cars and light trucks to be produced in model years 2012-2016 and 2017-2021. In 2015, NHTSA released a version of the model as modified to analyze options for future fuel consumption standards for heavy-duty pickup trucks and vans (e.g., Ford's F-350 pickup trucks and Mercedes' Sprinter vans). That version of the model also includes some more generally applicable refinements, such as more explicit representation of shared vehicle platforms and engines. The version released in 2016 concurrent with the Draft TAR has been refined yet further to improve the model’s approach to calculating fuel consumption impacts of different technologies, and enables simultaneous analysis of light-duty CAFE standards and heavy-duty pickup and van fuel consumption standards, accounting for some of the interactions between these market segments.


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

Contact:  Kevin Green (


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).  Many of these archives were compressed using 7-zip, which is available at

2016 Final Rule for Model Years 2021-2027 Heavy-Duty Pickups and Vans
2016 Draft TAR for Model Years 2022-2025 Passenger Cars and Light Trucks
2015 NPRM for Model Years 2021-2027 Heavy-Duty Pickups and Vans
2012 NPRM for Model Years 2017-2021 Passenger Cars and Light Trucks
2010 Final Rule for Model Years 2012-2016 Passenger Cars and Light Trucks
2009 NPRM for Model Years 2012-2016 Passenger Cars and Light Trucks
2009 Final Rule for Model Years 2011 Passenger Cars and Light Trucks