Study On Optimal Cycle's Determination Method And Simulation For Signals

In recent years, with the rapid development of auto industry in China, urban traffic pattern has changed dramatically. In the urban transport system, the intersection is a key node in the road network, which is directly related to the road capacity and efficiency. Urban traffic congestion most often occurred in the intersection, which not only led to traffic disruption, accidents increased and delays aggravation, also led to urban pollution increased. At the same time, the large differences of geographic and economic level lead to the traffic situations in all parts of our country are also different. In this context, the thesis chose the core of signal control in the city's single intersection-study on best signal cycle's determination method and simulation as the main contents, including the introduction, analysis of common method of signal timing, research of signal timing scheme, study on single intersection signal control design and simulation, optimization design and conclusions.The paper deep studied Webster algorithm which are often used in signal timing. Through the road design of single intersection, the thesis calculated timing and delay with using Webster algorithm. In VISSIM Traffic Simulation Software, it simulated and evaluated the design intersection, then generated the delay evaluation results. Taking calculation results and evaluation results of the design intersection as supporting data, the thesis compared them and in-depth analyzed the advantages and disadvantages and scope of the Webster method, then summarized the traffic situations in which Webster method is more suitable for calculating.For the high saturation intersection that Webster calculation is not accurate, the paper proposed appropriate cycle time's calculation method. It established the cycle time's optimal design model which used delay and road capacity as the pair goals of optimization, and solved the nonlinear problem of this model using Genetic Algorithm and Direct Search Toolbox of MATLAB. Meanwhile, the weighted coefficient of performance in this model changed with the traffic demand's diversification. Taking HePing Road with MinSheng Road intersection in Harbin as example to test and verify, and according to the traffic survey data, the thesis calculated respectively with Webster method and optimization method. Then by comparing the results of them, we found the optimization method could reduce the total delay and increase rode capacity to some extent of intersection. Finally, the thesis simulated the optimization result through VISSIM software.