Research On Traffic Assignment Of Expressway Construction Section Under Road Network

Due to the inability to meet the growing traffic demand,China's early construction of the expressway gradually ushered in the expansion stage.At present,there may be a number of expressways which have extension and expansion engineering in the expressway network.The number of traffic lanes in the construction section is constantly changing to disturb the normal traffic flow,and the vehicle will frequently carry on the driving behavior such as the split flow and the acceleration and deceleration in the construction section,which has great influence on the traffic flow,and the traffic capacity is greatly reduced.In recent years,scholars have carried out a detailed study of traffic assignment in the construction area,but the emphasis is on the study of method.It does not study the rationality of the traffic assignment of the construction area.Especially in the face of multiple expressways have extension and expansion engineering in the region,the rationality of regional diversion is particularly important.Based on the above situation,this paper first analyzes the theory and key problems of the road network traffic assignment and determines the key problems of the road network assignment,and studies the commonly used traffic assignment methods.The traffic organization form of the expressway reconstruction and expansion construction area is analyzed.The partition condition of the closed shoulder and the road occupied construction is taken as the partition condition,and the impedance function of the road section under different traffic organization conditions is analyzed.According to the operation characteristics of the traffic flow,the capacity of the construction area is corrected under the condition of the closed hard shoulders,and the classical BPR function is used as its impedance function.Under the condition of road occupation,the genetic algorithm based on the Measure of Effectiveness(MOE)distribution of traffic operation efficiency is used to calibrate the parameters in the simulation model of the construction area,and based on the mathematical statistics,the evaluation index of the trend difference is constructed.On the basis of the trend difference,the critical traffic volume of the construction section and the rational interval of large vehicle proportion are studied.Finally,the practical road impendence function of the construction area is constructed by using the optimal nonlinear fitting theory.Then,based on the analysis of the regional road network traffic assignment from the method level,this paper analyzes the steps of the road network traffic assignment scheme design and analyze the related road network,the OD matrix.The traffic assignment method of regional road network is studied from two levels: traffic assignment scheme and sub vehicle assignment.The regional road network of Anhui province expressway is selected as an experimental road network,and traffic assignment is verified and analyzed.