Research On Traffic Safety Design Method Of Urban Expressway Weaving Area

As the main framework of urban road,expressway plays an important role in relieving the traffic pressure and improving residents’ travel.However,with the increasing of vehicle ownership and the unique driving behavior of drivers in some sections,the expressway is often congested and the risk of accidents increases.Especially,in the weaving area,the traffic volume is large and the vehicle lane-changing behavior is frequent.The ratio of traffic accidents in this area to the total accidents of the expressway increases year by year.In this situation,the existing expressway design specifications have not yet given a complete design method for the weaving area.Therefore,the author proposes a traffic safety design method for expressway weaving area based on traffic safety consideration.By consulting the research status of relevant content,this paper introduces the relevant definitions of weaving area,analyzes the influencing factors of the safe operation of traffic flow in weaving area,and studies the formation mechanism of traffic conflict according to the driving characteristics of drivers.The author also analyzes the characteristics of traffic flow and drivers’ driving behavior in the weaving area,counts the traffic conflict data and determines the threshold of its severity.According to the analysis results of traffic survey,the model parameters of VISSIM micro traffic simulation software are corrected.Through the design of orthogonal experiment,the micro traffic flow operation data under the condition of changing the traffic flow parameters and geometric design parameters of the weaving area are obtained;the traffic conflict statistical data are obtained by analyzing the vehicle trajectories with conflict behavior in the traffic flow with SSAM software.Combined with the driver’s driving characteristics,the traffic safety characterization parameters of the weaving area are selected;the entropy weight TOPSIS method is used to weight the traffic safety characterization parameters,and the road safety coefficient index of the expressway weaving area is proposed as the basis for defining the traffic safety status of the weaving area.On this basis,the author also analyzes the relationship between the input parameters of the simulation experiment and the road safety factor of the expressway weaving area.On the basis of selecting the appropriate threshold value of road safety factor in expressway weaving area,the author puts forward the determination method of weaving area length,number of lanes,road longitudinal slope based on the consideration of traffic safety;combined with the micro traffic flow parameter characteristics and driver behavior characteristics,the lane marking type,vehicle direction sign setting position and speed control in weaving area are determined.