多车道高速公路路侧交通标志遮挡概率研究

Occlusion Probabilities of Road-side Traffic Sign of Multilane Expressway

为了计算不同交通量、不同运行车速情况下,多车道高速公路路侧交通标志视认中大型车对小型车的动态遮挡概率,将内侧车道小型车与外侧车道大型车车头间的垂直距离作为判断路侧交通标志遮挡的依据,根据视距几何关系确定多车道高速公路驾驶人在视认区域内视线被遮挡的最大和最小临界距离;建立路侧交通标志遮挡模型,根据视认距离确定内侧及外侧车道仿真路段长度,以0.1s为仿真步长,借助VISSIM交通仿真软件获取车辆车头坐标、与前车跟车距离等动态基础数据,实现高速公路交通标志遮挡概率计算过程的动态化。结果表明:外侧车道的车型、交通量、视认距离以及大小车运行速度都对路侧交通标志遮挡率有一定的影响;在交通量一定的情况下,驾驶人视线被遮挡的概率随着外侧车道大型车数量的增加而增大;在外侧车道大型车数量一定的情况下,驾驶人视线被遮挡概率随着小型车数量的增加而增大;在小型车速度一定的情况下,驾驶人视线被遮挡概率随着大型车速度的增大呈降低趋势;小型车速度增大时,驾驶人视线被遮挡的概率会有所提高。

In order to calculate the dynamic occlusion probabilities of road-side traffic signs of multilane expressways with different traffic volume and speed,and the maximum and minimum critical occlusion distances of multilane within the area of car drivers＇sight were calculated based on the geometrical relationship of visual range.The vertical distance between car on inside lane and truck on outside lane was taken as a judgment of the road-side traffic sign occlusion.The road-side traffic sign occlusion model was established.The dynamic data bases including the vehicle location coordinate and the following distance of car and truck were obtained by dint of VISSIM simulation software with the simulation step size of 0.1 s.The simulation length of the inside and outside lane was decided by the recognition distance.The results show that the vehicletype,traffic volume in outside lane and inside lane,recognition distance and the speed of truck and car have an impact on occlusion probabilities.The probabilities of missing the traffic sign increase with the increasing truck volume on outside lane and the car volume on inside lane,when the traffic volume is constant.Occlusion probabilities of car drivers＇sight decrease with the increasing speed of truck but increase with the increasing speed of car.