混合ACC车辆与人工驾驶车辆的交通流数值模拟

Numerical simulation of mixed traffic flow including ACC vehicles and manually driven vehicles

针对自动驾驶汽车与人工驾驶汽车混合通行的新型交通流模式,基于元胞自动机交通流模型,分别建立了人工驾驶汽车以及装有自适应巡航系统(ACC)车辆的运动规则,进而提出了混合ACC车辆与人工驾驶汽车的交通流模型.基于ACC车辆的常车头时距策略,分析了车头时距取值对交通流的影响,经过与实测数据比较,推荐了合适的车头时距值.研究结果显示,新型的混合交通流中依然存在自由流、同步流及宽幅运动阻塞,但是单纯ACC车辆交通流在中高密度区域则会出现均匀流动现象.车辆时空演化图显示ACC车辆的出现有利于提高交通流的整体流量、有效减少车辆集簇.研究结果可以为新型交通环境下的交通工程规划和建设提供理论指导.

In this paper,we investigate the new type of traffic flow with mixture of manual vehicles and vehicles equipped with adaptive cruise control(ACC).We propose a mixed traffic flow model,in which the updating rules of ACC vehicles and manually driven vehicles are presented respectively in a more realistic manner based on the cellular automaton traffic flow model.The“constant-headway time”policy is chosen for the ACC vehicles,the effect of which on traffic flow is analyzed.The value of the constant-headway time is recommended by comparing the simulation results with the measured field data.It is found that the three traffic phases,i.e.,free flow,synchronized flow and wide moving jams,also exist in the new mixed traffic flow system.However,the phenomenon of uniform flow is identified with ACC vehicles only when the density is moderate or high.Based on the spatial-temporal profiles of mixed traffic flow,it is found that the ACC vehicles help enhance the efficiency of the total traffic flow and reduce vehicles’congestions.