Study On Traffic Flow Control Of Urban Road Under Accidental Congestion

Accidental congestion is the phenomenon of traffic congestion caused by the occurrence of emergencies,which leads to the reduction of the actual capacity of the road.Accidental congestion has a great impact on traffic flow.Also,it is of great theoretical significance and practical value to improve the efficiency of traffic flow in the study of urban traffic flow control under accidental congestion.With the consideration of traffic flow and the actual traffic capacity to control the traffic flow,the control of urban road traffic flow under the existing accidental congestion takes the minimum of the total time,the maximum traffic capacity and the limited density as the goals.This paper studies the traffic flow control of urban road with the maximum capacity aimed at the situation when actual accidental consideration occurs,the number of traffic lanes reduces,the actual capacity decreases,the traffic density increases,and taking into account the situation of accidental duration of the traffic flow under accidental congestion.Results of this paper are as follows.Urban Traffic Flow control based on the cusp catastrophe in accidental congestion.Directed towards the characteristics of accidental congestion,using catastrophe theory,regarding the share of traffic volume in the carrying capacity as state variable,and the rate of traffic flow changes,the road remaining capacity changes as control variables,a cusp catastrophe model of urban traffic flow in accidental congestion is constructed in this paper.It selects the appropriate road resistance function and uses kinetic function to analyze the criticalstate of traffic congestion,which can get traffic flow in the critical mutation and stable mutation,and give the traffic flow limiting rate to control the traffic flow,traffic flow control scheme is given.Taking the field measurement of traffic conditions in the South Second Ring Road in Xi’an as an example,this paper analyzes the running state of traffic flow under different conditions,and illustrates the validity of the model.The results show that the model can better control the traffic flow.The road resistance function has great influence on the results.As for the application scope,in this paper,the road resistance function parameters are obtained by the specific data fitting,applicable to different types of roads,which is more in line with actual.Urban Traffic Flow control based on the swallowtail catastrophe in accidental congestion.Due to the greater influence of the accidental incident duration on the traffic flow,therefore,considering the accidental incident duration as the control factor,regarding the share of traffic volume in the carrying capacity as state variable,the rate of traffic flow changes,the road remaining capacity changes and the time rate of change as control variables,a swallowtail catastrophe model of urban traffic flow in accidental congestion is constructed in this paper.It discusses the dovetail mutation of bifurcation set in points plane.Then the critical state of traffic congestion is analyzed,and traffic flow control scheme is given.Taking the field measurement of traffic conditions in the South Second Ring Road in Xi’an as an example,this paper analyzes the running state of traffic flow under different conditions,and illustrates the validity of the model.The results show that the traffic flow can be easily mutation when the occasional accident lasts for more than 10 minutes.