基于元胞自动机的高速公路临时瓶颈交通流仿真

为研究强制换道及冲突点分布对高速公路临时瓶颈交通流的影响,在NS(NaSch)模型和STCA(symmetric two-lane cellular automata)模型的基础上,引入强制换道规则,根据瓶颈口上游驾驶员心理状态的变化,建立高速公路瓶颈交通流模型.在开口边界条件下,针对不同的安全换道概率、强制换道概率、冲突点距离和冲突区间长度参数,模拟得到瓶颈交通流量和换道频率与车辆到达率的关系.仿真结果表明,安全换道行为对系统流量影响小;强制换道行为是降低瓶颈系统最大流量的主要因素,当安全换道概率为0.5时,强制换道概率从0.0增加至0.1,最大流量下降了17%;冲突点距离的增加缓解了交通拥堵程度,当冲突点距离从1 cell增加至4 cell时,临界车辆到达率上升了4%;冲突区间长度对交通事故风险的影响较大,最大强制换道频率随冲突区间长度的增加而增加. 

Simulation of Temporary Traffic Bottleneck on Highways Based on Cellular Automaton

To study the influence of the forced lane changing and the distribution of conflict points on the temporary traffic bottleneck flow of freeways, a cellular automaton model was proposed considering the driver's changing psychology behavior. The new model combines the rule of forced lane changing with the NaSch (NS) model and the symmetric two-lane cellular automaton (STCA) model. Under open boundary, the relationship between the traffic flow at the bottleneck, the lane-changing frequency and the car arrival rate were obtained by simulation with different safe lane-changing probabilities, forced lane changing probabilities, distance between conflict areas, and length of conflict area. The results show that safe lane-changing behavior has little influence on the flow. The main factor decreasing the maximum flow is the forced lane changing behavior at the bottleneck. When the safe lane-changing probability is 0.5 and the forced lane changing probability changes from 0.0 to 0.1, the maximum flow decreases by 17%. The length of conflict area helps to reduce the traffic congestion at the bottleneck. When the range length of conflict area changes from 1 to 4 cells, the critical car arrival rate increases by 4%. The traffic conflict area has significant influence on the traffic safety risk, which could increase with the lane-changing probability.