Research On Lane Changing Behavior Of Freeway Merging Area Based On Ngsim Data

With the rapid development of society and economy,China’s transportation infrastructure and car ownership maintain a sustained growth trend.Among them,freeway has the characteristics of fast driving speed,large capacity,low transportation cost and driving safety,and plays an important role in the highway network.Its passenger and freight volume is increasing year by year,and the mileage is also increasing year by year.In the confluence area of freeway,due to the behavior of converging vehicles changing lanes,it often affects the driving of vehicles on the main road lane,resulting in traffic flow disorder,increased driving delay,reduced headway,reduced driving speed,multiple vehicle lane changing,multiple vehicle lane changing at the same time and other situations,becoming a high incidence area of traffic safety accidents,seriously affecting the entire freeway vehicles operation safety and traffic efficiency.Therefore,it is of great significance to study the operation characteristics of lane changing and merging behavior and the minimum safe distance of vehicle lane changing and merging to improve the traffic safety and traffic efficiency of freeway.Based on NGSIM(Next Generation Simulation)data set,this paper analyzes the characteristics of lane changing and merging behavior,establishes the minimum safe distance model of merging vehicle under different types of lane changing and merging behavior,and carries out simulation analysis and calculation verification on the model.The main research results are summarized as follows:First of all,this paper introduces the merging area of freeway,determines that the research object of this paper is the lane changing and merging behavior on parallel acceleration lane,divides the lane changing and merging behavior into three categories: free lane changing,cooperative lane changing and crowded lane changing,and analyzes the influencing factors of lane changing and merging behavior.Based on NGSIM data set,the track data of lane changing vehicles are extracted,and the beginning time of lane changing vehicles is defined as the time when there is obvious lateral displacement of lane changing vehicles.Then the track data of leading vehicles and following vehicles on the main road corresponding to lane changing vehicles are extracted,and the extracted vehicle track data is classified into free lane changing,cooperative lane changing and crowded lane changing Trace is classified to provide data support for later analysis and modeling.Secondly,according to the actual track data of the lane changing vehicles,the leading vehicles and following vehicles on the main road,the various measured data at the beginning of lane changing and the relationship between different data are statistically analyzed,and the merging gap,merging point distribution,driving distance and merging speed selected by three different types of vehicles at the beginning of lane changing are statistically analyzed.Then,the statistical analysis of the merging clearance and merging speed,the merging clearance and merging point position,and the relative distance between the leading car and the rear car and the merging car are carried out,and the operation rules of different types of lane changing merging behaviors are summarized,which lays the foundation for the following model establishment and simulation analysis.Finally,the environment of lane changing and merging is described,and the parameters in the model are defined.Based on the kinematic theory and formula,the minimum safe distance models between free lane changing,cooperative lane changing and crowded lane changing and between leading vehicle and following vehicle are established respectively according to the movement position changes of the merging car,leading vehicle and following vehicle in different types of lane changing and merging process.The model can be used to simulate the minimum safe distance between free lane changing,cooperative lane changing and crowded lane changing and between leading vehicle and following vehicle.Ensure that the merging vehicle will not collide with the leading vehicle and the following vehicle in the main road lane during the lane changing.Matlab simulation software is used to simulate and analyze the three minimum safe distance models of lane changing and merging behavior,and the safe area and non safe area of merging vehicle are obtained.The minimum safe distance model is calculated and verified by using the actual track data of free lane changing,cooperative lane changing and crowded lane changing extracted from NGSIM data set,and the calculation results are all the actual initial distances of lane changing and merging.All of them are greater than the minimum initial safe distance calculated by the model,which shows the rationality and applicability of the model.