Research On The Relationship Between Lane-Changing And Traffic Congestion

Lane-changing is common driving behavior in the process of vehicle driving influenced by driver factors, road conditions, vehicle characteristics and traffic flow states. Meanwhile, it affect the traffic flow operation:in certain traffic environment, lane-changing separates the rapid traffic flow and slow traffic flow, improving road utilization ratio. However, lane-changing will cause traffic congestion and jams when traffic flow is closely saturated. Researching on the conditions of traffic jams by the lane-changing, to manage and control the lane-changing behavior is of great significance for reducing traffic congestion.This paper, based on traffic flow theory, traffic engineering and traffic management and control measures, researches on relationship between the lane-changing and traffic jams. The specific content as follows:1) This paper, researching on the gap between the front vehicle and the following vehicle, based on subdivided car spacing model, analyzed the required headstock spacing when driver changes lane, given the definitions of smallest lane-changing interspace, critical queuing lane-changing interspace,critical congestion lane-changing interspace, no effect lane-changing interspace and the conditions of traffic jams by the lane-changing, introduced the characters of lane-changing under different traffic flow status, the different number of lanes, the driver and vehicle factor, obtained the conclusion that the abnormal and passive lane-changing occurred easily on the state of the unstable flow.2) Taken saturation degree as traffic congestion status indicators, lane change led to a decline in capacity. The decline of capacity consists of two parts:one is the extra space occupation while vehicles’lane change, the other is reduction of speed due to lane change, which expression has been given in this paper. In addition, the relationship of lane change and traffic congestion has been analyzed qualitatively with the traffic wave models and acceleration models in traffic flow theory.3) This paper selected the lane-changing of entrance ramp as the object of study. Used the mathematical statistics method to get the uniform distribution of speed interval which is corresponds to space headway in expressway, and the poisson distribution of vehicle arriving at the entrance ramp. Used the space headway car-following model and traffic wave model to get the probability of congestion when a vehicle arriving at ramp and changed lane.