Research On Offset Intersection Distance Based On VISSIM Simulation

With the enhancement of China’s comprehensive national strength and the continuous improvement of the people’s economic level,more and more cars began to enter people’s life,while facilitating people to travel,but also caused a series of traffic problems,traffic congestion,environmental pollution,noise pollution and other major problems have become troubling people.The intersection,as the pivot and node of the road,plays the role of transforming traffic flow in traffic operation.Scholars at home and abroad have conducted in-depth discussion and research on ordinary plane intersection,and have made great achievements in both traffic channelization and signal timing,which makes the traffic control technology of plane intersection increasingly mature.But in the city plane intersection,there is a special kind of intersection,dislocation intersection.The offset intersection consists of two or three t-shaped intersections with a certain distance between them,usually between 100 and 500 meters.The functional composition of the road at the dislocation intersection is generally one trunk road and two secondary trunk roads,and the traffic volume in the opposite direction is roughly the same.Such setting helps to separate the conflict points and make the traffic safer,but the traffic capacity is greatly reduced.And ordinary intersections has significant limitations of its control mode,if processes is not good will cause the traffic flow of deadlock,cause paralysis of the entire network,so for dislocation intersections,generally there are two solutions,one is through the transformation,will be transformed into a big intersections,through the intersections of the control method to control it,but this method has significant limitations,problems left over by history and demolition,etc,make the transformation dislocation intersections has a lot of difficulty,so people have come up with another kind of dislocation intersections savings plan,is to improve the way of the traffic control.At present,there are generally three control schemes for the offset intersection.One is to regard the offset intersection as an intersection and control it through the signal control of the intersection.The second is to coordinate the control of the two t-ports by imitating "green wave",and the third is to treat the misaligned intersection as two independent intersections for single point signal control.In order to minimize the adverse effect of the offset intersection on the urban traffic flow and realize the reasonable signal control of the offset intersection,it is necessary to make a detailed analysis of the offset intersection and make a comprehensive control of it.This paper analyzes the types and control modes of urban road intersections,and makes the following contents respectively:(1)through the related literatures and field survey of dislocation intersections,analysis of the types and summarizes the general urban road plane intersection traffic control mode,and on this basis,summarizes the characteristics of the dislocation intersections,and through the field survey data of dislocation intersections traffic volume,speed and so on are analyzed,and the analysis of the dislocation intersections distance under different traffic volume of the headway distribution conforms to the M3 distribution,and analyzes the factors that affect intersection distance.(2)By comparing all kinds of traffic simulation software,the selected VISSIM4.3 as this article research tools,and the actual survey data of simulation parameters for the calibration,first of all,the parameters of the expected speed and the driver behavior sensitivity analysis,selection of the parameters of high sensitivity,through a combination of genetic algorithm and SPSA algorithm,Matlab and VB language parameters calibration system for the development.(3)In real as the prototype,dislocation intersections by AUTOCAD software to draw different distance of dislocation intersections and import the VISSIM simulation software,based on the actual survey data,set the VISSIM simulation step input,run by a large number of simulation,the simulation evaluation concluded that different traffic volume and speed,the queuing length and queuing times under different distance.By analyzing the variation trend of queue length and queue times,the signal control mode suitable for the dislocated intersection with different traffic volume,different speed and different distance is finally determined.