Modeling And Application Of Left-turn Waiting Area At Mountain City Intersection

As urban traffic congestion,plane intersection is the important node of urban road network,the need to focus on optimization of left turn traffic flow is one of the important factors influence the operational efficiency of intersections,optimize left when area set is one of the main means of improving efficiency,mountain city limited plane intersection,turn left when area set up more refinement to consider.Construction of mountainous cities in order to accurately and scientifically left to line area model,in this paper,taking the advantages of the uav aerial video acquisition,several typical mountainous city plane intersection turn left to track behavior research,mainly from geometry model based on the intersection of line model building,based on the trajectory of the left micro uav aerial video data for line zone model building,turn left to line based on genetic algorithm(ga)district intersection signal timing optimization and so on,to research the specific as follows:(1)The method and condition of setting the left-turn waiting area are summarized,and the running characteristics of left-turn traffic flow are analyzed.(2)Construction of theoretical waiting zone model based on geometric characteristics of intersections.In this paper,on the left to narrow lane line area related research did not consider the mountain city,large slope,deformity of geometric characteristics of the part intersection,for the sake of clarity in the practical application for area whether "Settings",and "how to set up a" problem,this article left queue length analysis was used to study the with line area whether to set the boundary conditions and with line area need to set up the shortest length;Based on the conflict analysis method,the safe spacing of the waiting zone is defined and the interval model of the length of the left waiting zone is constructed.Based on the simulation,the time variation characteristics of left-turning vehicles passing the conflict point at different slopes are extracted.The influence of abnormal intersection,central isolation zone and lane attribute on the setting of traffic area was discussed.(3)The model of waiting zone is constructed based on the actual vehicle running track.In this paper,first of all,through the aerial video shooting and data processing of the uav,a batch of left-turn traffic trajectory data with characteristics of mountain city are obtained.Through the trajectory characteristic analysis and correlation function fitting analysis,the single-phase exponential attenuation function is determined to be the prototype of the basic function of vehicle left-turn trajectory.Then,through the geometric characteristics of the intersection,the starting point,the ending point and the conflict limit point are determined,the prototype of the left turn trajectory function is calibrated,and the function model of the vehicle left turn trajectory with the intersection geometric parameters as independent variables is constructed.Based on the curve line identification method,the left-turn trajectory of vehicles at the intersection is determined to be composed of two detent curves.(4)Study on signal timing method of left-turn waiting area intersection based on genetic algorithm.The previous section,the author of this paper build a left to line zone model,the fixed capacity calculation formula in HCM manual,and built with maximum capacity and minimum average delay and average number of parking at least as the goal,the phase green time,signal cycle for the multi-objective optimal parameters for the optimal solution model,the optimal solution can be got by using the genetic algorithm,combined with the actual case is verified.It provides support for the realization of urban fine management and control and the improvement of operation efficiency and safety level of urban intersections.Finally,the length of the waiting area is calculated by combining the theoretical model and the actual model,and the VISSIM simulation model is established.The simulation results show that the length of the waiting area calculated by the theoretical model is 29.5% lower than the length of the current waiting area.Compared with the length of waiting area calculated by the theoretical waiting area model,the average delay per vehicle decreased by 11.2%.