Seventy-five diesel vehicles were measured in China using a portable emissions measurement system (PEMS). Particular matter (PM) emission factors and gaseous emission factors for Euro 0 (E0), Euro 1 (E1), Euro 2 (E2), and Euro 3 (E3) trucks were obtained under highway, urban, and rural driving conditions. Vehicle emission regulations in China have successfully reduced carbon monoxide (CO), hydrocarbons (HC) and PM by 62, 56, and 72% on average. Most of the emission reductions were achieved when the control technology went from E0 to E1 in Xi'an, and E2 to E3 in Beijing, which resulted in PM reductions of 79% associated with highway driving and 60% associated with urban or rural driving. Emission levels of oxides of nitrogen (NO(X)) were not improved from previous emission control steps. Compared with Xi'an, the emission rate is lower in Beijing, which is strong evidence of the effectiveness of the present comprehensive emission control strategy in Beijing. Emissions were grouped into driving bins that corresponded to the energy demand placed on the vehicles. By using this binning approach, it was found that E3 trucks were successfully controlling the high emission rates in aggressive driving bins, which led to the low average emission for E3 trucks.