Driving Behavior Characteristics on Urban Expressway On- and Off-Ramp by Simulation

Traffic bottlenecks are easy to form on ramps, which restrict the capacity of urban expressway. The paper studied vehicle driving behavior characteristics on on- and off-ramps by simulator test, the utilization of acceleration section of on-ramps and that of deceleration section of off-ramps, speed transition on ramps, the merging position on on-ramps and the departure position on off-ramps were analyzed. The research would provide theoretical foundations for ramp alignment evaluation, traffic flow control on ramps and coordinated ramp control strategy optimization. It was discovered that vehicle acceleration did not distributed uniformly on ramps. Vehicle driving speed increases before acceleration section on on-ramps and it decreases before deceleration section on off-ramps, which indicates the acceleration and deceleration sections were not used adequately. The analysis of vehicle driving speed on the key positions showed that speed transition on off-ramps was better than that on on-ramps. The merging point where vehicle coming from ramps enter the expressway traffic flow clusters near the end of acceleration section, and the departure point where vehicle coming from expressway enters the ramp clusters on the half part of transition section. This phenomenon indicates that the transition section of on- and off-ramp was not used with expectation.