Regional Traffic Signal Control Based On Coordinated Path Chains Of Intersection Clusters

Signal control is an important means to alleviate urban traffic congestion and improve road network traffic efficiency.A scientific and reasonable signal control strategy not only needs single-point signal control and trunk line coordination control,but also needs the implementation of regional traffic signal control at intersections with the closely related road network.Previous studies on regional traffic signal control mainly focused on intersection correlation,division method,and signal coordination design,it is obvious to find that the existing research objects of intersection correlation are still mainly adjacent intersections,and few scholars have studied the correlation between multiple intersections.The partial division method has the problems of incomplete consideration of factors and relatively rough division.In addition,the selection of coordination trunk lacks the directionality and asymmetry of coordination demand,and the priority of multiple coordination trunks is often ignored in signal coordination design.Thus,the thesis focuses on intersection correlation degree,division method,and signal coordination design,the specific contents are as follows:(1)In the aspect of the correlation degree of intersection.Since the intersections belonging to the control sub-region have a certain degree of correlation,it is difficult to effectively divide the control sub-region only by the correlation degree of adjacent intersections.Combined with the correlation between adjacent intersections,non-adjacent intersections of the regional road networks and the correlation between intersections belonging to the same control sub-area,the thesis improves and revises the concept of an intersection group.The analytic hierarchy process is employed to comprehensively evaluate the influence of intersection spacing,road runoff and signal cycle on the correlation of intersection groups.According to the evaluation results,the correlation degree of adjacent intersections and intersection groups are established,which can provide a theoretical basis for the classification method.(2)In terms of the method of the intersection group division.Based on the key factors such as the correlation degree of adjacent intersections,the correlation degree of intersection groups,the number of intersections and the modularity of road network,the objective function and constraint conditions of intersection group division are set respectively,so as to establish the intersection group division model.By comprehensively comparing the advantages and disadvantages of the existing partition methods,the traditional breadth-first traversal partition algorithm is selected as the basis based on t the intersection group division model,the network node degree and node saturation are introduced to improve the randomness of node selection,the parameters such as traffic density,spatial distance and search direction are introduced to improve the path search of the algorithm.Improved breadth-first traversal partitioning algorithm effectively improves the accuracy and reliability of partitioning results.(3)As for the coordination design.Combined with the directional and asymmetric characteristics of intersection group coordination control requirements,the concepts of coordination path chain are proposed to characterize the specific coordination objects in the intersection group;the Whitson model is modified by introducing parameters such as road runoff and path travel time,and the judgment method of coordinated path chain is given.According to the key elements of the coordinated path chain,such as the number of intersections,road grade and traffic flow,the improved binary relative comparison method is used to complete the priority setting of the coordinated path chain.Taking the coordinated path chain as the object,a regional signal control model for the coordinated path chain is established.(4)To verify the effectiveness and rationality of the proposed method,the vissim software is used to simulate and evaluate different schemes in the core area of Jinhua Jindong District.The results indicate that 1)compared to the current situation,the proposed method can reduces the average delay of the total intersections of the regional road network by24.78%,the average number of stops by 16.70%,and the average queue length by 30.78%;and 2)Compared to the regional traffic signal coordination control based on the division of control sub-regions,the proposed method in the thesis reduces the average delay of regional total intersections by 7.92%,the average number of stops by 2.02%,and the average number of stops by 19.22%.The thesis analyzes the importance of multi-intersection correlation degree to the division results,and conducts research on regional road network intersection groups,including the division of intersection groups and selection of coordinated main roads.The research results can divide the regional road network,also alleviate urban traffic congestion and improving the efficiency of the road network.