Effects of intersection lane configuration on traffic emissions

Lane configuration at intersections has been mainly applied to mitigate traffic congestions and reduce travel delay, while rarely considered for emissions reduction. In response to the worsened air pollution, this paper investigates the effects of lane configuration on traffic emissions and offers effective advises to traffic engineers. The integration of traffic simulation model VISSIM and VSP (vehicle specific power) based emission model is selected to build scenarios and analyze the traffic emissions under different lane configuration designs. Five indicators in total are covered in this paper, which are average delay per vehicle, average number of stops per vehicle and the total emissions of CO, HC and NOx respectively. The result shows that the existence of exclusive lane set (no matter broadened or not) indicates a significantly effect on the characteristics of the traffic flow and emissions at intersections. The comparisons between different lane configuration scenarios provide us three suggestions: the high traffic operation efficiency and low traffic emissions share the same design preferences; it is important to set an exclusive signal phase or waiting area for left turn exclusive lane (whether broadened or not); a right turn exclusive lane is always useful.