CARBITS is a market simulation model for the passenger vehicle market in California. Professor David S. Bunch developed CARBITS for the ARB during 2003-04 under a contract with the University of California, Davis. Its primary purpose is as a scenario analysis tool to evaluate market response under alternative regulation scenarios.

For purposes of this Final Report, the version of CARBITS developed during 2003-2004 will be referred to as “CARBITS 1.0.” CARBITS 1.0 was requested by the ARB to meet specific needs for their work under AB 1493 regulating motor vehicle greenhouse gas emissions, and was developed within a short time frame to accommodate their schedule.

The project was feasible because it was possible to base CARBITS development on preexisting research results developed under an earlier University of California-Institute of Transportation Studies research program. Although time and monetary constraints prevented development of a full range of features, ARB staff successfully used CARBITS 1.0 in support of the climate change regulation adopted by the Board in September 2004.