Simulation analyses of two on-ramp lane arrangements

Abstract

Ramps are vital pieces of infrastructure connecting city traffic networks to freeways. The performance of a ramp is to some extent determined by the on-ramp lane arrangement. In this research, our primary aim is to evaluate the performance in terms of vehicle emissions for two on-ramp lane arrangements: added lane and zip merging. We estimate the CO2 emissions on the basis of the speed, and acceleration of vehicles in accordance with the comprehensive modal emission model (CMEM), and then analyze the impacts of traffic volume and heavy goods vehicles (HGVs) on emissions. The effect of main road traffic flow on emissions for the two on-ramp lane arrangements are analyzed under scenarios with traffic volumes of 800, 1000, 1200, 1400, 1600, and 1800 vehs/hr/lane. Meanwhile, the relationships between CO2 discharge and various proportions of HGVs (2%, 4%, 6%, 8%, and 10%) for both on-ramp lane arrangements are evaluated as well. We eventually present emission contour charts for the two on-ramp lane arrangements based on the possible combinations of traffic volumes and HGV percentages.