Study On Safety Facilities Of Traffic Flow Organization At The Exit Of Eight-Lane Expressway

With the rapid development of economy,the traffic volume of expressways in China is growing rapidly,especially in developed areas.The traffic volume of existing four-lane expressways is saturated and the level of road service is reduced,which makes it difficult to meet the demand for use.In view of this phenomenon,eight lanes are proposed as the main form of reconstruction and expansion.Compared with the four lanes,the eight-lane expressway exit has different vehicle operation mode,traffic flow characteristics and driver behavior characteristics.The increase of lane-changing distance,the increase of conflict points and the imperfection of safety facilities at high-speed exit make the interchange exit a black spot of the eight-lane Expressway accident.Therefore,this paper proposes a study on traffic flow organization and safety facilities at the exit of eight-lane Expressway interchange,aiming at improving road-related auxiliary facilities and driving safety level.Firstly,the data of highway traffic accidents and the status quo of traffic safety facilities are analyzed,and the causes of highway exit accidents are obtained.At the same time,the traffic flow characteristics of eight-lane highway exit are compared and summarized.Secondly,it analyses and calculates the visible area and the critical condition of vehicle occlusion of signs with different support modes,calculates the occlusion probability under various traffic conditions with the help of VISSIM traffic simulation software,and gives the exit of eight-lane Expressway Based on the advantages of various support modes,the characteristics of traffic signs at different locations at the exit of eight-lane Expressway and foreign experience and norms.Thirdly,by measuring the driving data of drivers at the exit of eight-lane expressway,the driving behavior characteristics of drivers are analyzed,and a new lane-changing model is put forward.Based on this model,the leading distance of signs is calculated,and the reasonable setting distance of signs is given by referring to psychological knowledge.Through the above calculation,the reasonable setting position of exit signs of eight-lane expressway is given.Finally,by analyzing the current situation of the use of existing traffic safety facilities and referring to the experience of setting up at home and abroad,the optimal design of marking,anti-collision facilities and other traffic safety facilities is given.Through the above research,this paper establishes a more humanized and rationalized eight-lane freeway interchange exit traffic safety facilities installation program,in order to improve the traffic conditions at the exit,improve safety and reduce the accident rate.