Research On The Setting Of Advance Guide Sign At The Bidirectional Eight-lane Expressway Exit

With the sustained and rapid development of social economy,the expressway traffic volume grows rapaidly,many of four-lane expressway which is built completion in the early year has emerged gradually serious traffic congestion phenomenon and unable to meet the traffic needs,expansion of them has become eight-lane expressway.Vehicles in eight-lane expressway are running absolutely faster,the number of them is increased greatly,the degree of freedom of the driver changing lanes is significant increase while the number of accidents also increased.In particular,the accident rate is more than four-lane,six-lane's.The reason of these is the free-way exit safety not perfect.Clear advance guide sign can increase driver's psychological pressure,lead changing lane,provide road information,guide the direction of purpose.So it is important to set up a reasonable export indication marking at the expressway exit.Firstly through the introduction of the advance guide sign on expressway,and combining the existing problems,this paper determines the advance distance of expressway exit as the main research object.By analyzing the process of vehicles driving from the expressway exit,the calculation model of the advance distance of the expressway advance guide sign is established,and the distance is determined by the length of changing lance.Then,the paper analyzes the changing behavior of the expressway exit and the effect factors of the vehicle's changing lane,and establishes the model of distance of the vehicle's changing lane,analyzes the time of changing lane in the lane changing model.Through the actual survey,using the Hi-Drive driving behavior acquisition equipment,gets the distance of the vehicle's changing lane at the first service level.At the same time,using VISSIM simulations get the distance of the vehicle's changing lane at the different service level and verify the credibility of the simulation results.Finally,according to the distance of the vehicle's changing lane and the duplicate setting of guide sign,the paper obtains the distance of the advance guide sign,put forward the suggestions of the location of the advance guide sign.In this paper,with the science and technology in the Shan Xi province transportation hall communication project based on the safety and efficiency of lane highway speed management research(project number:14-32 –R),to the bidirectional eight-lane expressway exit direction sign set research as the main object,mainly based on the lane changing distance of advance guide sign position of setting research.