Research On Coordinated Control Of Arterial Roads In The Case Of Accidental Congestion

With the substantial increase of vehicle volume,the problem of traffic congestion is also increasingly severe.Accidental traffic congestion increases the difficulty of evacuation control due to uncertainty and derivative.And the arterial roads of the city as the main artery in urban traffic network,the size of its capacity is the key factor to determine the service level of the urban roads.When there is an accidental traffic congestion on the arterial road,if still using the original signal control,it is likely that the queuing vehicles will be accumulated,and even generate queue overflow,seriously affect the capacity of the traffic network.In order to reduce the accidental congestion impact on the arterial traffic flow,in this paper,the signal coordinate is applied to the upstream multiple intersections at the congested arterial road,so that the traffic flow through the congested section is allocated to other roads of the network in advance to reduce the flow of traffic into the congested sections.The main work is as follows:(1)According to the theory of traffic wave,the propagation law of congested traffic flow is studied.The process of propagation is divided into three stages:the initial stage,the development stage and the serious congestion stage.The traffic wave model is based on the traffic wave theory,it analyzes the wave characteristics of the accidental congestion wave in the bottleneck section,simulates the queuing length of congested sections under different traffic demand.(2)This paper tries to control the upstream intersections of the accidental traffic congestion and reducing traffic flow into congested sections.The main method is to compress the green time of the correlation phase of the upstream intersection according to the size of the remaining traffic capacity of the congested road section and the relationship of intersections,assign the compressed green time to the non-related phase according to the proportional principle.Using the coordinated control to reassign the traffic flow,control the traffic flow into the congested sections so as to reduce the speed of congestion propagation.improve the overall traffic capacity of the arterial roads and ensure the "benign" diffusion of the accidental traffic congestion until the network back to normal.(3)Coordinate control on arterial roads is simulated though VISSIM simulation software.Contrasting ordinary signal control methods,simulation projects are designed on the different traffic flow conditions of crowded sections.The results showed that both peak traffic flow and flat traffic flow,this method can improve the capacity of all roads.