Variability of Heavy Duty Vehicle Operating Mode Frequencies for Prediction of211 Mobile Emissions

摘要

The paper discusses a new geographic information system (GIS)-based modal211u001eemissions model being developed with EPA and Georgia Tech to account for vehicle 211u001eload conditions that will significantly improve the spatial resultion of 211u001eemissions estimates. The GIS-based modal research model employs detailed subfleet 211u001eengine and emissions characteristics and the speed/acceleration profiles for 211u001evehicle activity along links in the transportation system. Composition of the 211u001evehicle subfleet affects the amount of emissions produced under various operating 211u001econditions, dependent upon the load induced by the vehicle and driver, and the 211u001ephysical constraints of the vehicle. The aggregate modal frequencies are compared 211u001eacross vehicle classes to show differences in how heavy duty vehicles are 211u001eoperated.