Comparisons Between Vehicular Emissions from Real-World In-Use Testing and EPA MOVES Estimation (SWUTC/12/476660-00021-1)

This research study developed a methodology to perform mandatory dynamometer vehicular emissions tests on real roads, performed on-road emissions tests, and compared the test results to the estimates using the current EPA emissions estimation model. Currently, mandatory vehicular exhaust emission tests are performed on chassis or engine dynamometers using the Federal Test Procedure (FTP)/Supplemental Federal Test Procedure (SFTP) drive schedules. Based on the developed real-world in-use emissions testing methodology with using a modified test vehicle, authors could follow the FTP/SFTP drive schedules while the vehicle was driven on real roads, and measure emissions during the in-use on-road FTP/SFTP emissions testing. Emissions from the vehicle during the testing were measured, analyzed, and compared to estimated emissions using the current EPA emissions estimation model, MOtor Vehicle Emission Simulator (MOVES). The authors observed discrepancies between the measured data and the MOVES estimates, especially when associated with cold-start emissions. More detailed analysis results, along with the detailed test methodologies, are provided in this report.