Study On The Geometric Parameters For The Speed-Change Lane Of The Expressway And Safeguard Measures

The speed-change lane is the critical facility for the transition of traffic and lane conversion and speed of traffic on the highway entrance.Research shows that the highway in gateway location of the accident rate is much higher than other sections,and the speed-change drive geometric design to improve the highway entrances traffic capacity and service level,improve highway entrances and exits of road traffic safety plays an important role.It is of great significance to study the geometrical design parameters and safety measures of highway speed drive.This paper starts from the investigation and analysis of the accident of the expressway entrance and exit,and deeply studies the causes of the accident of the expressway entrance and exit.Based on the observation and data analysis of the four interchange at the Bao-mao Expressway,the traffic characteristics of the expressway lane are systematically studied.On the basis of analyzing the traffic characteristics of expressway entrance and exit and the problems of geometric design of acceleration and deceleration lane,the main research object of small parking spaces is to use the acceptable gap theory of traffic flow to meet the main line service level.Time distribution model and acceleration of lane vehicle.Based on the theory of secondary deceleration,the operation of the shunt vehicle in the deceleration lane is carried out.The process is divided into the gradual section,the first slowdown,the second deceleration of the three processes,to build a deceleration lane length calculation model.Based on the analysis of the traffic characteristics of the entrances and exits,and at the same time,the paper puts forward some suggestions on the geometric design parameters of the speed-change lane in line with the traffic characteristics of expressway in China.On the basis of analyzing and summarizing the technical use of expressway safety and security measures in our country,this paper also analyzes the signs and marking of expressway lane,the guarantee of sight distance,the speed control,and the improvement of pavement safety from the point of view of system improvement.,The specific optimization and improvement measures are put forward,which have a positive effect on preventing and reducing the occurrence of expressway entrances and exits.