Research On Micro Traffic Behavior Of Car-Following And Lane-Changing

The traffic flow theory deeply analyzes the interaction between vehicles,which can reflect the essential characteristics of traffic flow to the greatest extent,and help to solve all kinds of traffic problems better.As the basic theories of microscopic traffic flow,car-following theory and lane-changing theory aim to accurately reflect the characteristics of human driving behavior,reproduce the actual human driving behavior,and have practical significance in guiding traffic organization and management,reduce traffic congestion and so on.In this paper,the carfollowing model and lane-changing model are improved to make them more accurate in line with human driving behavior.The improvement contents include:Aiming at the defects of the optimal velocity function of the existing car-following model,an improved optimal velocity function is proposed;based on the lateral gap of vehicles departing from the lane centerline,a car-following and lane-changing combined model is constructed.The research contents of this paper are as follows:(1)An improved optimal velocity function is proposed.This paper analyzes the shortcomings of the existing traffic flow models in the study of car-following behavior,and strictly proves the wrong correspondence between the headway and the optimal velocity in the optimal velocity function by using mathematical induction.The interval between the vehicle heads in different stages is separated by the segment function,and the driving state of the vehicle is judged by the newly established correspondence,and the optimal velocity function is improved;(2)Based on the improved optimal velocity function,a car-following model is proposed.Firstly,the stability of the model is analyzed by using the small disturbance method,and the stability conditions of the model are obtained,which are verified under periodic boundary conditions.Secondly,the dynamic performance of car-following model based on two different optimal velocity functions is analyzed.The analysis results show that the car-following model based on the improved optimal velocity function is better than the car-following model based on the traditional optimal velocity function in dynamic performance,which can not only solve the problem of continuous increase of headway,but also realize the dynamic adjustment of headway in traffic flow integration and interruption;(3)A car-following and lane-changing combined model with time-varying lateral gap is proposed.Combined with the car-following model considering lateral gap,the lane-changing behavior of vehicle is regarded as car-following behavior with lateral motion,and the two common driving behaviors are unified in the same model.The lane changing simulation results show that the car-following and lane-changing combined model can not only dynamically adjust the change of headway caused by lane changing,but also reasonably describe the motion of lane-changing vehicles and their rear vehicles.