The Transportation Analysis and Simulation System (TRANSIMS) contains a vehicle
emissions module that estimates tailpipe emissions for light and heavy duty vehicles and
evaporative emissions for light duty vehicles. It uses as inputs the emissions arrays
obtained from the CMEM model. This paper describes and validates the TRANSIMS
emission module and compares its emission estimates to on-road emission measurements
and other state-of-the-art emission models including the VT-Micro, CMEM, and
MOBILE6 models. Thirteen different runs were conducted to compare emissions from
field measurements to the trends in emissions obtained form the above-mentioned four
models. The results indicate that the TRANSIMS model provides consistent trends of
estimated Carbon Monoxide (CO) and Hydrocarbons (HC) with field data, while
inconsistent trends of estimated Nitrogen Oxides (NOx). However, the magnitude of
emissions estimated by TRANSIMS is closer to the field data than those obtained form
the other models; MOBILE6, CMEM, and VT-Micro
