| With the rapid development of China's social economy and the continuous adjustment and change of urban structure,traffic flow on many urban roads presents obvious unbalanced operation characteristics and causes traffic congestion.For example,the traffic fluctuation of each turn-around traffic flow at the same entrance during peak and peak periods obviously leads to congestion caused by a long queue of turn-around traffic flow,while the utilization rate of other lanes is lower,or the obvious tidal characteristics on the roads entering(leaving)the city lead to frequent congestion,while the utilization rate of roads in the opposite direction is lower.Traditional signal control methods have limited effect on the improvement of the above traffic congestion.It is necessary to transform lane functions in combination with variable lane technology to adapt to uneven traffic flow direction at intersections and uneven traffic flow direction at road sections.Therefore,how to comprehensively optimize the lane function configuration and signal control at intersections is of practical significance for improving the utilization rate of space-time resources at intersections and improving the operation efficiency of intersections.Firstly,the paper sorts out the typical comprehensive optimization models of lane configuration and signal control at home and abroad,and analyzes the common phase schemes of unbalanced traffic flow.Then,it analyzes the lane function division modes and lane function types that can be selected by different phase schemes,which provided the theoretical basis for establishing the comprehensive optimization model of lane configuration and signal timing.Then,taking the release scheme with superimposed phases as an example,considering the constraints of lane length,number of entrance and exit lanes,and taking the maximum reserve capacity(traffic capacity)as the target,a comprehensive optimization model of lane configuration and signal timing is established.The model is an optimization problem with nonlinear constraints under linear objectives.It can be transformed into a finite number of Binary-Mixed-Integer-Linear-Programs(BMILPs)and can be solved quickly by commercial solvers such as CPLEX.In order to improve the adaptability of the aforementioned model to certain traffic demand fluctuations,the paper then analyzes the rationality of the lane allocation scheme that does not need to be changed frequently when the intersection adapts to the demand fluctuations in a certain period of time,thus determining the logical control framework of variable signal timing,and further establishing the signal timing optimization model based on the solution in chapter 3,which aims at minimizing the total delay of the intersection in that period of time.This model is an optimization problem with nonlinear constraints under nonlinear targets and can be solved quickly by genetic algorithm.Finally,taking the intersection of Jin Quan Road and Jin Furong Avenue in Chengdu as an example,the results of chapter 3 and chapter 4 are applied to control.VISSIM simulation results show that the optimization scheme in chapter 3 reduces the average delay of intersections by 22.6% and the maximum queue length by 39.7% compared with the existing schemes,while the queue length of traffic flow is always smaller than the corresponding short lane length.Compared with the optimization scheme in chapter 3,the optimization scheme in chapter 4 improves the average delay at intersections by 16% ~ 44%.The maximum queue length is basically maintained at a low level,thus verifying the effectiveness of the third chapter model and the fourth chapter signal control method. |
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