Research On Optimization Of Linkage Control Method Between Urban Expressway And Conventional Road

Urban expressway is the main framework of road network,which mainly meets large capacity,long-distance travel.In recent years,due to the expansion of city scale,urban road network congestion is becoming increasingly severe,and the connection between express roads and conventional roads has become a “traffic bottleneck” because of reduced speed and mismatched traffic capacity.The lack of planning and inefficient management methods for early road network have made it difficult for Expressway to play its rapid and efficient role.Therefore,based on the theory and method of induction control,this paper synthetically analyzes the traffic state difference between the main road of the expressway and the adjacent auxiliary road and the upper and downstream intersections,and optimizes the coordinated control method of the link area between the expressway and the conventional road.The operating efficiency of the expressway system is optimized.Firstly,considering the road types and their respective characteristics of expressway and conventional road,the connection characteristics and traffic problems between expressway and conventional road are analyzed.By analyzing the connection mode between expressway and conventional road,the paper summarized the common interchange types and their respective applicable characteristics.For different types of exit and exit ramps,based on the existing specification values,consider the main road traffic volume,headway and other traffic flow parameters influencing factors,according to the specifications and traffic flow conditions to calculate the minimum spacing of various types of ramps recommended The value,which is more in line with the changing process of the on-ramp traffic,then,the traffic organization method of off-ramp and auxiliary road is optimized.At the same time,using the theory of acceptable clearance,a calculation method for the design length of the interlaced section between the main road and the ground was proposed.Secondly,based on the theory of expressway ramp control,the applicability of the basic method of ramp control was analyzed and a coordinated control strategy was proposed.Besides,based on the concept of hierarchically coordinated control,the ratio of the remaining capacity of main roads on the expressway and the ratio of ramp steering were taken into account,and the optimal operation status of the main road on the expressway was taken as the control objective.For determining the ramp regulation rate of expressways,the coordinated control optimization method between ramp and adjacent intersection was put forward from the control of the key points in the connecting area through adjusting the signal control scheme of the intersection on the auxiliary road.Then,the proposed coordinated control method was simulated to verify the effectiveness of the coordinated control optimization method by using the Vissim simulation software.Finally,from the angle of alleviating congestion and improving the performance of road network,multi-ramp coordinated control between expressways and conventional roads was analyzed.From the aspect of connecting area control,the main road dynamic model and the ramp queuing model were combined to establish a coordinated control model which regard the shortest total travel time of the expressway system as the control objective.The variable tolerance method is combined with the genetic algorithm as an operator to optimize the genetic algorithm,and the optimized genetic algorithm is used to solve the model optimally.Combined with Vissim simulation,the effectiveness of multi-ramp coordinated control optimization method is analyzed.The results showed that the multi-ramp coordinated control optimization method could reduce the total travel t ime and improve the traffic efficiency of the entire regional road network,and provide the reference for the traffic organization and control of the urban expressway and conventional road connection area.