• Many users of EPA’s MOBILE model are developing regional or local fleet characterization data to more accurately predict mobile source emissions. Vehicle identification number (VIN) decoder software is often used to process registration data or observed fleet data to characterize on-road vehicle classes and age distributions. Limitations in VIN decoder software affect the accuracy of these predicted fleet distributions.The proposed research will build upon recent VIN decoder work to:

1. Summarize the important vehicle and engine technology variables that have been used in advanced emission rate models or may be used in future models; 2. Identify all commercially available VIN decoders, and 3. Procure and evaluate the ability of these VIN decoders to produce accurate fleet characterization data for use with current and advanced models. Based on this evaluation, the researchers will scope out a research plan and budget to develop a public domain VIN decoder software.