A classification of expressway traffic flow characteristics based on different distances between on-ramp and off-ramp

This paper focuses on the influence on traffic flow characteristics of distance between on-ramp and off-ramp in expressway. In this research, those characteristics include traffic flow rate, average speed and average density. Based on VISSEVI, we calibrated key parameters and a calibrating procedure is proposed. Then we simulated scenarios with different distances from 100m to 1000m. Analyses of the distance's influence on traffic flow characteristics are studied using simulation results. A step further, 3 modes are classified out of different distances and 2 thresholds are proposed. The two thresholds are within 100-200m and 500-600m and if distance varies through these, traffic flow characteristics will change significantly. Finally, as for verification, we compared 3 scenarios of simulation with reality. In the future, different control strategies may be applied due to different conditions.