Evaluating speed differences between cars, light-duty trucks, and vans for emissions modeling

The percentage of sport-utility vehicles, light-duty trucks, and passenger vans in the on-road light-duty fleet is steadily increasing. The implications for modeling emissions from on-road vehicles are significant since light-duty trucks produce, on average, more emissions than passenger cars. Although not frequently considered in calculating emission rates, differences in the average speeds of passenger cars, light-duty trucks, sport-utility vehicles, and passenger vans may influence emissions. This paper investigated whether the different classes of passenger vehicles operated differently on-road. Spot speed studies were used to determine differences in operating characteristics for three subgroups of the passenger car fleet. Results are presented for studies on freeways and arterials.