Research On Coordination Control Method For The Exit And Entrance Ramps Of Freeway And The Junction Intersection

Freeway and urban road are governed,independently designed and constructed by different departments in our country.The connecting section between freeway toll station and urban signalized intersection is a special area of the two types of road networks,and it is also a road bottleneck point.The traffic conditions of the connecting road section directly affect the transportation of the two major road networks.With the increasing traffic demand,problem of traffic congestion of the connecting road sections has become increasingly prominent and cannot be ignored.In order to adapt to the development demand of safety and fluency of China's transportation industry,systematic research is urgently needed to establish an integrated,systematic and intelligent management system for freeways and urban roads.The main research content of this paper includes the following four parts:First,the road traffic correlation analysis was carried out to demonstrate the necessity of coordination control between the entrance and exit ramps of freeway,the toll station and the junction intersection.Secondly,in view of the toll station connects to the single signal intersection,the minimum delay or the maximum traffic capacity of the target region was taken as the control goal,and preventing queue overflow of toll station ramps and toll plaza,intersections and connecting sections were taken as a constraint,aiming at the two traffic conditions of unsaturated and saturated,coordination control methods for the exit and entrance ramps of freeway and the junction intersections were proposed respectively.On the one hand,the method realizes the coordination of the number of vehicles passing through the toll station and the signal timing of the intersection.On the other hand,it excavates the function of the toll station to regulate the traffic flow,and ensures the passage of the freeway entrance and exit traffic flow.The case simulation analysis was used to verify these characteristics and rationality of the model.Then,aiming at the situation that toll station connects to the two intersections by double-entry and double-exit traffic flow,the queue length between each target node was taken as a constraint,a multi-objective coordination control model maximizing traffic capacity in saturated traffic conditions was built.This coordinated control method can rapidly disperse the exit traffic of freeway to the surrounding intersections,avoid the queue overflow of the link segment and it can limit traffic flow into the freeway main line according to its acceptable traffic volume.Case study and simulation analysis of Beicun Toll Station of North Second Ring Freeway in Guangzhou were carried out to verify that the coordination control of the toll station and the junction intersections can effectively control the queue length of the link segment and balance the congestion of the road network.Finally,in order to avoid traffic congestion transferring to the surrounding intersections,fuzzy control concept was introduced.Firstly,the entrance and exit ramps,toll station and junction intersections were taken as a whole node where traffic produced and dissipated,and then regional fuzzy control were made for them as well as the surrounding intersections to adjust the green time of each phase and balance the traffic flow to the surrounding intersections.Finally,the feasibility and superiority of the regional coordination control method were verified by case analysis.