Research On Perimeter Control Method Of Congested Region With Dynamic Boundary In Urban Road Network

The traffic system is a dynamic and complex system,and the traffic condition of the road network will change in both time and space dimension.Traditional control methods are often aimed at traffic control region with a certain fixed boundary without considering the boundary change of control region caused by congestion propagation,which has certain limitations.This paper relies on the National natural science youth foundation project?network traffic detection based on the temporal and spatial feature extraction and algorithm of rapid evacuation(No.61304195)and Anhui Province Natural Science Foundation Project ?space traffic network situation conversion mechanism and rapid evacuation study(No.1408085QF111).Based on the Macroscopic Fundamental Diagram theory,a control method of urban traffic congested road network with a dynamic boundary is proposed,the main contents include the following.Firstly,considering that the traditional dynamic sub-region partitioning method has large number of calculation in the recalculation process,based on the traffic density of the road section,the concepts of combined influence degree and united and combined influence degree are applied to repartition the heterogeneity traffic region,so as to adapt to the dynamic boundary control.Secondly,based on the traffic wave theory,taking the boundary intersection of the congested area at the initial moment as the research object,the change of the congestion state at the boundary intersection is studied by analyzing the queuing length,and the boundary intersection is divided into three types: outputted trend intersection,imported trend intersection and passed trend intersection.This paper analyzes the changing trend of the boundary range of the traffic jam area caused by the influence of the diffusion or dissipation of traffic congestion,and measures the range of the traffic congested region by the total length of the links in it.Thirdly,considering the change of MFD shape caused by the boundary change of the congestion area,a 3d-MFD with the total length of the links in the congestion region(the third dimension)is formed.On this basis,the sliding mode variable structure control is applied on the boundary of congested region to realize the control effect on the congested region.Finally,the actual urban road network is used for case analysis.By comparing the PI control method under no boundary change,PI control method considering dynamic boundary and SMC method considering dynamic boundary of congested region(SMCDB),four evaluation indexes,the accumulation of vehicles,trip completion rate,total delay and fuel consumption of the road network are analyzed.The results show that the SMCDB method is better than the previous two methods in the four indexes,so the proposed control method can effectively improve network operation efficiency,alleviate traffic congestion,and avoid local excessive congestion.