Current models of vehicle fuel use and emissions are based on Vehicle Specific Power which were found to be less predictive when compared to models that are based on direct engine data, such as engine revolutions per minute (RPM) and manifold absolute pressure (MAP). These engine data can readily be obtained through the on-Board-Diagnostics (OBD) port of the vehicle. This project intends to replicate OBD data in traffic simulation through the analysis of field data and the generation of predictive models. The UF/NCSU team will develop an OBD device class within a custom traffic microsimulation tool (CORSIM-NG), which will replicate the behavior and functionality of real OBD devices.