Research On The Setting Technology And Security Measures Of The Left Entrance And Exit At Main Line

The transportation infrastructure construction of China is becoming more and more perfect.As an important infrastructure of the transportation industry,the highway network scale is also gradually expanding.As the key area of expressway,the entrance and exit of expressway are difficult in design and security.At present,the expressway network of China is gradually extending to cities and mountainous areas,and the route layout is restricted greatly.The use of right entrance and exit may cause excessive consumption of environmental and economic indicators,so it is necessary to consider the use of left entrance and exit.The design index of the left side entrance and exit is not clearly defined in the code of China,and the relevant design index is difficult to meet the safety requirements of the left side entrance and exit.Therefore,this paper focuses on the design technology and security measures of the left design index at main line.Based on the accident situation of the left side entrance and exit at main line,this paper analyzes the safety influencing factors and traffic flow characteristics of the left side entrance and exit,and determines the main factors to be considered in the technical research.Referring to the research results at home and abroad,combined with the traffic flow theory and traffic capacity evaluation index of the main line entrance and exit,the applicable conditions of the left side entrance and exit line are determined.Secondly,according to the analysis of the advantages and disadvantages of acceleration lane with different types,this paper proposes that the left acceleration lane should adopt parallel type;based on the measured data of UMRR radar,extract the speed and acceleration of vehicles in the acceleration lane,and determine the characteristic parameters of acceleration lane.Based on the analysis of mathematical statistics theory,it is concluded that the headway of the left lane of the main line obeys the negative index distribu tion of displacement,and the length of waiting section is calculated.Based on the analysis of the driver’s line of sight changes in the left acceleration lane,the length of the transition section meeting the requirements of the sight distance is calculated.According to the above calculation and analysis results,combined with the research model of the acceleration lane on the left side of main line,the acceleration lane setting technology of the left entrance is proposed.Based on the analysis of the deceleration characteristics of vehicles on the left side of main line and the advantages and disadvantages of different deceleration lanes,it is proposed that the left deceleration lane should be parallel type.Based on the measured data of UMRR radar,the speed and acceleration transformation of vehicles in the characteristic section are extracted,and the characteristic parameters of deceleration lane calculation are determined.According to the relevant calculation model of deceleration lane,the deceleration lane setting technology at the left exit is proposed.Finally,by analyzing the process of left side diversion of drivers,combining with waiting insertable gap model and lane change model,this paper calculates the reasonable setting position of left side exit warning signs,and puts forward the layout of signs and the setting method of road signs,and calculates the length of left side diversion influence area and confluence influence area,and puts forward the division form of left side exit speed limit area.The research results of this paper can provide a theoretical basis for the setting of the left side entrance and exit at main highway,and provide a reference for the setting of urban roads and other related entrance and exit.