Research On Traffic Organization And Design Technical Index Of Two-way Left Turn Lane Of Urban Roads

In recent years,with the increasing automobile volume in China,traffic congestion and accidents of urban road have become more serious.Horizontal intersection is a high-incidence place for road traffic accidents.In the two-way four-vehicle road section with dense roads,tight land use and no signal control,the rationality of left-turn traffic flow plays an important role in improving road traffic capacity and reducing conflicts.The developed countries have adopted many effective new organization methods for the left-turn traffic at the intersection,while the optimal design,application and evaluation of the left-turn traffic organization in China are still in initial stage,which is far from the developed countries.Therefore,research on optimizing the traffic organization of left-turn traffic has important application significance.Based on the comparison of the left-turn traffic flow organization of several commonly used intersections at home and abroad,the characteristics of the two-way-left-turn-lane(TWLTL)traffic flow and the traffic organization are researched.Then,the simulation models are established by VISSIM software,and the vehicle delay,queue length and number of conflicts are selected as the evaluation indicators.Under the combination of different hourly traffic volume of main road,ratio of left-turn traffic volume,traffic volume of branch road and branch road spacing,the grey correlation analysis method is adopted.The range of traffic volume suitable for TWLTL of different types of roads are proposed.After that,based on traffic flow theory and traffic safety theory,the geometric design indexes of TWLTL are studied.The recommended value of minimum lane width,minimum spacing of adjacent intersections and spacing of the same direction turning arrows are proposed.Finally,the setting method of traffic safety facilities such as the signs and markings of TWLTL are studied.The research results have important reference significance for the application of two-way left-turn-lane.