Research On Geometric Design And Signal Control Of Shift Synchronous Left-turn Lane At Road Intersection

With the continuous growth of my country’s economy,people’s purchasing power and travel demand for motor vehicles continue to increase,and road congestion has become more and more serious.Related departments have also proposed various solutions for this.Intersections,as the key nodes of urban road traffic,are also the most prominent nodes that produce traffic problems.How to make full use of the spatial-temporal resources of intersections and further explore the potential capacity of roads under the existing conditions is the purpose of this paper.By consulting a large number of domestic and foreign literature on traffic organization and signal timing optimization methods,the existing results are summarized and studied.Firstly,this thesis expounds the organization principle of left-turn traffic flow at intersections and sorts out the spatio-temporal characteristics of left-turn traffic flow under the conventional mode.On this basis,several common traffic organization methods are elaborated in detail,which will pave the way for the design of shift synchronous left-turn lane schemeSecondly,the thesis expounds the definition and traffic rules of the shifted synchronous left-turn lane intersection,and qualitatively analyzes the prerequisites for setting it.Based on the different functions of different parts of the left-turn entrance road at the intersection after the canalization design,the left-turn storage lane and the shift synchronous left-turn lane were established respectively,and the theoretical calculation method of its length and the value of the length of the lane change section were proposed.Refer to the method,and proposed the setting method for the supporting facilities such as the road section separation belt and the traffic sign marking line.Then,after in-depth research on the characteristics of periodic traffic flow under signalized intersections and the principle of signal timing,the pre-signal phase at the lane change section and the three-phase signal timing scheme at the intersection are proposed for the shift-synchronized left-turn lane intersection.By studying the operating characteristics of the left-turn traffic flow under this scheme,the calculation method of the opening and closing time of the pre-signal phase is given.Combining the pre-signal phase opening and closing time and the theoretical calculation method of the delay of the vehicles in each direction,the total delay of one cycle at the intersection is used as the control performance index,and the signal timing optimization model is constructed.Considering that the model problem requires the optimal solution under nonlinear and constrained conditions,the particle swarm algorithm is selected as the solution method of this model after analysis.Finally,based on the analysis of an intersection in Lu’an City,this paper demonstrates the feasibility of setting shift synchronous left turn lane,and expounds the implementation process of channelization transformation.By using VISSIM simulation software,the simulation platforms of three different channelized intersections,i.e.the conventional intersection,the left-turn reverse variable lane intersection and the shift synchronous left-turn lane intersection proposed in this paper,are established,and the measured peak and flat peak traffic volume data are imported for simulation verification.The results show that the shifted and synchronized left-turn lane intersection design scheme and timing scheme proposed in this paper can significantly reduce the average queue length,average vehicle delay,average parking delay and travel time under different scenarios,and improve the traffic capacity of the intersection.