Optimal Study On Signal Timing Based On Pre-signal Intersection

As the key node of urban road network,intersection has a vital influence.Reasonable traffic organization can effectively increase traffic capacity and reduce delay.With the emergence of unconventional intersections,more and more attention is paid to new intersections at home and abroad.Based on some basic theory of pre-signal and setting mode of continuous flow intersection,this paper corrects the existing problems of continuous flow intersection.Mainly from the continuous flow intersection layout mode,left turn lane length,primary and secondary intersection signal coordination timing and other aspects of improvement.It provides a theoretical basis and positive practical significance for the setting and application of intersections in China.The operation mode and conflict point of the left turn traffic flow at the traditional intersection are analyzed,and the problem of the conflict point of the existing continuous flow intersection is improved to reduce the conflict point of the intersection.Based on the theory of traffic flow,queuing theory and domestic and foreign scholars,the calculation method of left turn lane length is summarized and calculated from the operation characteristics.Includes left-turn storage length,left-turn lateral gradient length,left-turn approach length.The left turn lane length model composed of these three parts can get the distance between the primary and secondary intersections and pave the way for the later signal timing.According to the four-direction controlled continuous flow intersection in this paper,some setting conditions and timing principles are put forward,which mainly consider the phase difference between the primary and secondary signals,the situation of vehicle queue overflow,and the release of the most vehicles in the green time.A comprehensive optimization model of lane length and signal timing based on the minimum delay of intersection vehicles is constructed.The intersection of Zhangqian Road and New cement Road in Dalian City is selected as a case study,and the current intersection and the modified continuous flow intersection scheme are compared and analyzed by VISSIM simulation software.Combined with the model,the lane length and signal timing are calculated.By comparing the queue length,delay,driving time and parking times,the results show that all the indexes of the optimization scheme are reduced,which shows the superiority and feasibility of the method in this paper.