Study On Route Hierarchical Control Strategy Of Controlled Intelligent Road Network

In the process of urban modernization development,traffic congestion has brought huge losses to social and economic development.In order to better alleviate the traffic congestion within the city,this paper will explore this problem from the perspective of macroscopic fundamental diagram(MFD)and traffic assignment.The Macroscopic Fundamental Diagram is a carrier for the aggregation of traffic information in urban homogeneous areas.The main content of this paper is to use the dynamic characteristics of the road network mapped by MFD combined with the theory of traffic assignment and guidance to provide the decision basis for the driving path of vehicles in the road network.The previous route guidance schemes based on MFD theory generally consider the centralized vehicle summary scheme,which is effective for the balanced distribution of vehicles at the macro level,but lacks the path information of vehicles in the detailed traffic network.In order to further improve the detailed level of vehicle path guidance information under the framework of MFD,the reasonable distribution of vehicles in the road network can be induced in real time by considering the coordinated and unified expression of vehicles at the macro and micro levels of the road network.The specific research contents can be summarized as follows:(1)The macroscopic fundamental diagram theory is summarized.On the basis of analyzing and summarizing the macroscopic aggregation characteristics of traffic network,the macroscopic mapping relationship of homogeneous road network is obtained.(2)A hierarchical vehicle route control model was constructed.Firstly,the significance of macro route is expounded.Then a traffic network reduction scheme is constructed on the basis of heterogeneous macroscopic routes.A macroscopic equilibrium distribution model of traffic demand is established on the basis of reduced network.The main significance of this step is to calculate the macroscopic distribution of traffic network demand over the road network.Successive averages are used to solve this model and the resulting vehicles distribution results are also centralized.Heterogeneous macro paths in the reduced network are used to activate the micro paths of the road network,and then the macroscopic aggregated flow is transferred to the micro network scale.Logit path selection model is used to redistribute the traffic flow.(3)The solution designs.The solution and verification of the path hierarchical control model are carried out on the SUMO simulation platform,and the real-time interaction of test network traffic information is realized mainly through Python calling the Traci interface of SUMO.The simulation operation process is a dynamic real-time feedback process.Python uses Traci to read the simulation information of each step for path layered control calculation and uses Traci to feedback the calculation results to vehicles.(4)Analysis of simulation results.The real-time state information and network operation indexes of the test network under three vehicle path control strategies are analyzed.The results show that the path layered control is effective and superior to the comparison strategy.