Research On Traffic Coordination Control Methods For Urban Over-Saturated Arterial

With the development of social economy,the number of vehicles is increasing.Oversaturated condition during peak hours is more and more frequent,which can cause traffic congestion,resulting in increased vehicle delays and travel time.Traffic congestion caused by oversaturated traffic conditions has brought huge economic losses and social costs.Therefore,it is necessary to propose an effective control method to coordinate urban traffic.Intersection as the bottleneck of traffic signal control is the basis of traffic coordination control,while arterial as the important holder of urban traffic is the main object of traffic coordination control.This article analyzes the evolution law of traffic flow of intersection and arterial under oversaturated traffic condition to realize the traffic coordination control of urban arterial roads.To deal with the traffic control problem of urban intersections under oversaturated traffic condition,this article proposes an improved model-based predictive control method.The method contains three modules:model-based predictive control,queue overflow identification,and queue overflow control.The optimal green time splits scheme can be computed online by the module of model-based predictive control.The module of queue overflow identification can be applied to detect potential queue overflow in real time.The module of queue overflow control can prevent vehicles on the upstream section from entering the section suffering potential queue overflow.In this paper,the simulation evaluation results obtained from the VISSIM4.3 show that the delay in improved model predictive control algorithm can be decreased by 11.6 percentage compared with adaptive signal control method and 13.2 percentage compared with the model-based predictive control.In addition,the maximum queue length during the period when queue overflow occurs frequently is low with our proposed method.Therefore,the results verify this method can improve both delay and queue length of oversaturated intersections.To solve the problem of traffic coordination control of arterial roads under an oversaturated traffic condition,this article proposes an improved delay minimization method along oversaturated two-way arterials.The method takes into account both the influence of traffic density on the speed of vehicles on the road and the randomness of vehicles arrival.The optimization goal is to minimize the delay of two-way arterial,which can optimize the green splits and the coordination parameters of offset.Finally,the performance of the proposed method is verified by the simulation evaluation results.The experimental results show that the improved delay minimization method proposed in this paper can effectively control the queue length under oversaturated traffic state.Furthermore,the delay in this method can be decreased by 5.4 percentage compared with the novel delay minimization method and 13.6 percentage compared with the traffic coordination control method without offset optimization.Finally,the proposed method can balance the delay level of different road section,which can directly reflect the efficiency of the improved delay minimization method on traffic coordination control under oversaturated traffic condition.