快速路入口区域车辆跟驰行为研究

Car-following Behavior at Expressway Entrance Area

快速路入口区域车辆跟驰行为及安全间距会受到汇入车辆影响。为了探索快速路入口区域车辆的跟驰行为,利用无人机在200 m高空对快速路入口区域进行高空悬停定点拍摄,并利用Tracker软件提取了车辆速度、车辆横纵坐标、加速度等参数。采用跟驰距离、相对跟驰速度绝对值及跟驰片段长度指标对快速路入口区域车辆的跟驰行为进行判断,确定了快速路入口区域跟驰行为判定准则。在此基础上,对交通流变化、车道分布、入口形式对跟驰行为的影响进行对比分析。研究发现:快速路入口区域车辆跟驰距离均值为26 m,车辆跟驰距离集中分布在15~28 m;相对跟驰速度绝对值均值为0.75 m/s,且90%车辆相对速度绝对值小于1 m/s;车辆跟驰距离和后车跟驰速度随交通流增加逐渐减小;快速路最内侧车道车辆跟驰距离和跟驰速度大于中间车道;直接式入口的主线车辆跟驰距离和跟驰速度大于平行式入口。本文研究成果可为快速路入口区域跟驰行为参数标定及管控提供参考依据。

Car-following behavior and safety distance at the expressway entrance area will be affected by merging vehicles.In order to explore car-following behavior of vehicles at the expressway entrance area,UAVs were used to take aerial hovering fixed-point shots of expressway entrance area at an altitude of 200 m,and Tracker software was used to extract vehicle speed,vehicle transverse and vertical coordinates,acceleration and other parameters.Car-following distance,the absolute value of the relative car-following speed and the length of car-following segment were used to judge car-following behavior at the expressway entrance area,and the judgment criteria for car-following behavior at the expressway entrance area was determined.Then the impacts of traffic flow change,lane distribution and entrance form on car-following behavior were compared and analyzed.It is found that the average car-following distance at the expressway entrance is 26 m,and the car-following distance is concentrated at 15~28 m.The mean absolute value of relative car-following speed is 0.75 m/s,and the absolute value of 90%vehicle relative speed is less than 1 m/s.Car-following distance and car-following speed show a downward trend with the increase of traffic flow.Car-following distance at the innermost lane of the expressway is greater than that at the middle lane.Car-following distance of the main-line vehicle at the direct entrance is greater than that at the parallel entrance.The research results can provide a reference for the calibration and control of car-following behavior parameters in the expressway entrance area.