Analysis of driving characteristics and estimation of pollutant emissions from intra-city buses

摘要

Intra-city buses provide essential transportation and mobility services in cities. However, most of the buses in Indian cities run on diesel fuel causing significant emissions and air quality issues. This study aims to quantify the emissions from the buses during peak and off-peak periods using second-by-second activity data collected using global positioning system (GPS) receivers. Four-bus routes plying within the city of Chennai in India was selected and second-by-second speed and acceleration was used to determine the operating mode of the bus. Corresponding emissions were estimated using vehicle specific power (VSP). Results show that the average speed of the bus during peak and off-peak periods were 17.8 kmph and 21.5 kmph, respectively; the corresponding percentages of time idling were 27% and 22%. Further, the percentage increase in total emissions of CO 2 , CO, HC and NO x from the bus during peak periods with respect to off-peak periods was 17%, 16%, 37% and 21%, respectively. This study provides useful insights regarding the operating and emission characteristics of buses that will be valuable to policy makers in improving their service and efficiency.