Study On Boundary Feedback Control Strategy Of Urban Traffic Zone Based On Macroscopic Fundamental Diagram

With the rapid development of the current economy,unimpeded traffic has become an important guarantee for economic development.However,as the number of car ownership increases year by year,the existing road traffic infrastructure is far from meeting the growing traffic demand.The accompanying traffic congestion,frequent traffic accidents and environmental pollution problems also plague urban residents and city managers.This has not only had a major impact on daily travel,but has even seriously affected the economic development.In recent years,traffic congestion has become increasingly serious.It is impossible to solve this problem only by improving the transportation infrastructure.It is also necessary to support the traffic control strategy more reasonably and effectively to restore the normal order of traffic.Firstly,according to the relevance between adjacent intersections in the road network,the adjacent intersections in the road network satisfying the relevance threshold are divided into the same traffic control sub-region,and the selection of the relevance threshold is studied.It was verified by simulation road network.Then,based on the Macroscopic Fundamental Diagram theory,the Macroscopic Fundamental Diagram characteristics of the traffic control sub-region are obtained,and the optimal number of accumulated vehicles corresponding to the maximum number of completed vehicles in the traffic sub-region is determined.When the number of vehicles inside the traffic sub-region exceeds the optimal number of accumulated vehicles,the boundary control strategy is used to maintain the number of vehicles in the sub-region near the optimal number of accumulated vehicles by adjusting the proportion of vehicles entering and leaving the sub-region at the boundary intersection.In order to ensure that the traffic inside the sub-region is kept in an optimal state.At the same time,this paper proposes an asymmetric signal control method for the boundary intersection signal lamp,and gives the signal phase and timing setting method of the boundary intersection.In order to consider the normal walking of the pedestrian and the opposite lane,the minimum green time limit is added.At the same time,in order to prevent vehicles outside the boundary from queuing to the upstream intersection,the queue length limit is increased.When the queue length of the vehicle is too large,the release time in the corresponding direction is increased to ensure that the congestion does not spread further.Based on the above research,this paper develops and designs a set of urban traffic boundary feedback control simulation experiment system,which is mainly used for visual display of boundary control strategy and experimental data processing.Several other control strategies are provided in the system to compare the control effects and provide more reasonable decisions for city managers.