A Quantitative Analysis on Urban Bus Emissions and Energy Consumptions under Different Road Speeds and Dwell Time

A model for estimating gas or electric bus operating conditions and emissions (or energy consumptions) is developed to quantify urban bus emissions and energy consumptions under different road speeds and dwell time at different locations. This model is developed by more than 750 thousand GPS records of 5 bus lines and a large amount of floating vehicle data. The result shows that in road areas, the road speed of mixed traffic flow has a greater impact on bus emission and energy consumption than dwell time at bus stops. As the road speed increases by 5 km/h, the relativebus speed increases by 0.17, and the relative emission factor and relative energy consumption factor decrease by 0.11 and 0.06, respectively. In the bus stop area, the dwell time at the bus stop has a greater impact on bus emissions and energy consumptions than the speed on the road.As the dwell time decreases by 15 seconds; the relative bus speed increases by 0.11; the relative emission factor and relative energy consumption factor both decrease by 0.06. Increasing the speed on the road at different locations does not always significantly reduce bus emissions and energy consumptions. Thus, cooperative control of bus operation efficiency and emissions (or energy consumptions) should be carried out in the comprehensive traffic system.