Research On Acceleration Lane Length Based On The Time Headway Distribution

The existing research results show that the merging area of the freeway acceleration lane and the main line has always been a frequent accident section that needs to be paid attention to,and the main forms of accidents are mainly rear-end collisions and lateral collision accidents,and the main reason for rear-end collision and lateral collision accidents is the large difference between the merging speed of vehicles in the acceleration lane and the speed of the main line.There are many factors that affect the speed of vehicle merging,of which the length of the acceleration lane setting is the most important factor.Therefore,based on the characteristics of traffic flow,the length model of acceleration lane is established,and the optimal length of freeway acceleration lane is studied,and the specific process and method are as follows.Firstly,the parallel acceleration road section of the southern section of the Weihe River Bridge of Xianyang Airport with good vehicle operation is selected.The UAV is used to collect the traffic flow data of the section,and the video data is preprocessed by Kinovea software and Tracker software,and Finally,traffic flow data such as traffic flow,vehicle speed,vehicle acceleration,and vehicle merging point of 1070 vehicles were obtained.Secondly,the correlation analysis is used to analyze the traffic flow data,and the analysis results show that the merging speed of vehicles in the acceleration lane is related to the merging point,and the merging point is affected by the distance of the front of the vehicle in the outer lane of the main line.Different main line traffic corresponds to different headline time distance distribution,so based on different main line traffic flow,a vehicle convergence probability model based on the first-order and third-order Erlang head-time distance distribution is established.Finally,the acceleration lane is divided into three segments according to the vehicle acceleration characteristics of the acceleration lane.Based on the acceleration-velocity linear model,the acceleration segment length model is established.Based on the vehicle merging probability model of the first-and third-order Erlang head-to-head distribution of vehicle convergence,the corresponding influent section length model is established,the first-order influent section length model is suitable for the situation of traffic flow 0～250veh/h,and the third-order influent section length model is suitable for the traffic flow of 500～750veh/h.The length of the gradient segment is set according to the specification.The length model of the collected road segment data is used for regression fitting verification,and Vissim is used to simulate the length model.The verification results show that compared with the traditional acceleration lane length value,the road safety set according to the length value calculated by the model is improved.According to the model,Eventually,a recommended value of recommended length of acceleration lanes is given.