The Reaserach On Signal Timing Of Closely-space Intersection

Due to the limitation of land use in urban road traffic planning,there are a large number of closely-space intersection in china. The upstream and downstream traffic flow in the closely-space intersection would conflict with each other because of the short distance.When the traffic flow is saturated, it is very easy to appear the problem of Queuing upstream in the bottleneck which resulting in congestion .On the basis of summarizing the existing research results, this paper analyzes the characteristics of the closely-space intersection. Starting from the definition and determination of closely-space intersection by summarizing the existing literature. The method which is proposed in the "Standard For Urban Road Design" is used as a judgment method for closely-space intersection .In the meanwhile, the paper analyzed the characteristics of the closely-space intersection and summarized four main problems. It also analyzed the most prominent problems which is queue upstream and described the causes of formation and the process of causing paralysis at intersections and then affecting the whole network under the deadlock condition. Secondly, on the basis of summarizing the existing intersection signal control method, combining with the characteristics of closely-space intersection, the paper selects commonly used coordination control method to optimizing the signal control of the closely-space intersection. Then the paper discusses the existing research , point out that some parameters of this kind of method is difficult to obtain and the model has sumption precondition so that it is difficult to use in practical applications.According to the defects of the existing research, the closely-space intersection is controlled by fuzzy control method without precise mathematical model and complex parameters. Firstly, the paper designs fuzzy controller of a single intersection with queue length as input and green time as output. Then, according to the characteristics of the closely-space intersection, the paper designs secondary modified fuzzy controller which is based on the traffic condition in order to minimize the number of retention the section vehicle in the section.The paper also designs the fuzzy evacuation controller to control the section when it is about to queuing upstream. The controller has two stage. The first stage outputs the upstream reducing green time and the downstream increasing green time by inputting the queue length of the downstream bottleneck section and the queue length of the main phase of the upstream.The second stage adjusts the parameters which is output by first stage based on the queue length of the other phases at each intersection.The paper confirmed the effectiveness of the fuzzy control scheme which is Combine with this two fuzzy control schemes by being compared with the original scheme a,the coordinated control optimization scheme and an optimization scheme with queuing constraints through the simulation analysis.