Research On Signal Design Optimization Method Of Single Intersection Under Coordination Control Constraints

With the continuous development of urbanization and motorization in China,the contradiction between supply and demand of urban traffic is increasing.Traffic congestion is becoming more and more serious.Due to restrictions in resources and economic input,urban road construction and scale expansion are unlikely to last for a long time.The need to improve road traffic efficiency is growing.There is an urgent need to strengthen the intelligent management and optimal control of urban traffic,especially coordination control.In the optimization design of urban road traffic signals,if the coordination control of road network and path is not considered,the signal scheme which takes the best running effect of a single intersection as the design goal has no significance.However,optimizing the performance of each intersection is also an important part of coordination control design.In this regard,urban road network signal design optimization method of single intersection under coordination control constraints was studied in this paper.The main research work completed and the research results obtained are summarized as follows.1)Urban road network signal coordination control mechanism was analyzed.Refinement method of road network coordination control was studied,which can refine the minimum coordination control unit segment into the coordination path,and realize the refined description of various coordination control requirements in the road network using the coordination path chain and the coordination path set.Optimization method of coordination path sets was studied.Moreover,the structure and constraints of coordination controls were analyzed and determined.2)Consider the problem of the traffic demand at the intersection under the coordination control constraints,aiming at the shortcomings of the usual signal timing design methods when dealing with the intersection split allocation under the complex overlap signal phase structure,the general intersection split allocation method was studied.Firstly,an objective function of split allocation based on traffic demand was proposed.Then the basic split allocation model and the multi-round split allocation model of intersection were built.Finally,the allocation process of split and phase time was given.And a procedural intersection split allocation method was designed.The model and method can optimize the green time of overlap phase movement and non-critical movement through multi-round allocation of split and phase time,which can effectively improve the overall traffic efficiency at intersection,and make the design of split allocation scheme more scientific and reasonable.3)Considering the traffic demand at the intersection,based on the general intersection split allocation method proposed in this paper,simultaneous optimization method of phase sequence design and timing were studied.Firstly,according to the coordinated phase sequence,phase time and other constraints,considering the pedestrian crossing demand,the basic model for phase timing was bulit.Then combined with the coordinated phase setting at intersection,the simultaneous optimization method of phase sequence design and timing were studied.Finally,the simultaneous optimization process was presented.A phase design and timing simultaneous optimization method was designed which can improve the overall intersection traffic efficiency.4)Considering maximizing the benefits of coordination control,based on the existing arterial road green wave coordination control algebraic method,the green time allocation method of coordinated phase at arterial road intersection was studied.Firstly,the basic signal timing was determined according to the intersection traffic demand.Then the optimal cycle and coordinated phase sequence were determined according to the existing algebraic method.The basic green wave bandwidth of the coordination direction was calculated.Finally,the green time of the bottleneck intersection was adjusted until the scheme of maximum bidirectional green wave bandwidth was obtained,and through which the optimization of the bidirectional coordinated phase green time was realized.The method proposed provides a basis for obtaining the global optimal green wave coordination control scheme.5)Under the constraints of coordination control,considering maximizing the benefits of coordination control,based on the existing green wave coordination control scheme design method for regional road network,the optimization method of signal phase time at each intersection in regional road network was further studied.Aiming at the phase time problem of each intersection of the regional green wave coordination control optimization model under the split phasing mode,the model and method to allocate phase time of each inlet of the intersections based on the constraints of the adjacent phase time and the goal of the maximum road network green wave bandwidth were studied,which maximize the coordination control benefits of the regional green wave coordination control optimization model.