GPS data has been applied to traffic and emissions analysis of operating passenger cars (OPC) for many years, however, there is little research on the difference between the occupied state and vacant state. Based on GPS data, this study focused on the emission differences of two states (occupied and vacant state) on different dates (weekdays, weekends, and holidays). Combined with the software MOVES and emission rate model, four emission calculation methods were proposed to reveal the emission characteristics of OPC at different levels (mesoscopic- and micro-level). The results show that the emission factors (EFs) of the vacant state were about 0.6 times that of the occupied state, and the emission of vacant state accounted for about 20% of the total emissions. Moreover, EFs and total emission had a significant weekday/non-weekday pattern which was related to peak hours. This study provides basic comparative algorithms for passenger car emissions.

vehicle emission;operating passenger cars;GPS data;MOVES;VSP