Study On Traffic Flow Equilibrium Condition Of The Controlled Network

With the increasing number of motor vehicles,the problem of urban road traffic congestion is becoming more and more serious,which affects the traveler's normal work and life.In recent years,the construction and development of intelligent transportation system become more and more consummate,that makes timely accessing all types of traffic information in the road network to be possible,at the same time it provides a good opportunity for the dynamic monitoring and management of urban traffic.In this context,the study of urban traffic management based on the theory of automatic control has been paid more and more attention by academics.Those research results provide a new perspective and direction for the study of urban traffic network under the condition of controlled road network.Due to the lack of obtaining all the information of the road network,the traditional urban traffic area control method can't accurately determine the equilibrium of road network traffic flow,as a result the effect is not satisfied;while the controlled network can obtain the complete information of all the roads in the network,and with the help of the dynamic agglomeration of the macroscopic fundamental diagrams.the running rules of the vehicles under the traffic flow equilibrium condition is clearly displayed,which provides evidence for the formulation of effective and feasible congestion control strategy.Based on the macroscopic fundamental diagrams of the controlled network,this paper studied the traffic flow equilibrium condition.which mainly includes the following aspects:(1)This paper analyzed the basic characteristics of the traffic flow of the controlled network from the network status characteristics of the controlled network and the distribution characteristics of the network traffic flow;after that this paper got the equation for calculating the flow rate of the inflow and outflow of the road network boundary to describe the traffic flow dynamics;then this paper put forward the criterion of the traffic flow equilibrium condition of the controlled network,at last this paper analyzed the traffic status of the network in and without equilibrium condition.(2)Based on the traffic flow equilibrium theory and the characteristics of macroscopic fundamental diagrams this paper proposed a bi-level programming model for traffic flow equilibrium of controlled network,which considered the impact of cumulative vehicles on the overall operating state of the network.The upper model was the inflow and outflow rate control model for the road network boundary vehicles,which was used to describe the relationship between the boundary and the overall traffic status of the network;the lower model was the user optimum dynamic traffic assignment model,which was used to describe the path selection behavior of the travelers in the network.In this paper,the MSA algorithm was used to solve the model,during the process of the solving,this paper introduced the road traffic transport state equation into the lower model,then obtained the relationship between the traffic flow on the boundary and the overall traffic flow of the network,after that this paper realized the solution of the model,at last the boundary accurate control strategies was received.(3)This paper verified the effectiveness of the boundary control strategy by analysis of examples with the Sioux Falls test network.By comparing the average speed of vehicles?the average delay of vehicles and the total delay of the network before and after implementation of the control strategies,the results showed that the boundary control strategies based on the traffic flow balance condition of the controlled network can effectively improve the operation of the vehicle within the network,improve the overall traffic efficiency of the network and mitigate regional traffic congestion.In this paper,through the study on traffic flow equilibrium condition of the controlled network,we obtained the criterion of equilibrium condition and the running state equation of controlled network under equilibrium condition.Then,with the bi-level programming model,this paper checked the control strategies got from the flow equilibrium condition of the controlled network can effectively improve the efficiency of network traffic.In the future,we will further study the specific control strategy of network under the flow equilibrium condition.