Study On Congestion Characteristics Of Freeway On Ramp Confluence Area Considering The Influence Of Intersections

In recent years,the confluence area of the on ramp of the expressway will have frequent congestion during the peak period.The traffic disturbance caused by the confluence of the on ramp and vehicle following is the key to the frequent congestion of the expressway.The existing research on the confluence area of the expressway often assumes that the confluence of the ramp is uniform,without considering the impact of the intersection on the upstream of the on ramp.The in-depth study of the traffic flow in the confluence area of Expressway on ramp considering the impact of intersection is of great significance to reveal the congestion characteristics of Expressway and formulate congestion control strategies.Based on the trajectory data,this paper studies the macro characteristics and micro behavior.The main contents of the full text are as follows:Firstly,this paper selects the confluence area of typical urban on ramp and expressway,and uses the deep learning algorithm to obtain the vehicle trajectory data in the UAV video.Based on the analysis of the traffic characteristics of the road section based on the trajectory data and the three-phase traffic flow,this paper believes that the generation of the general mode of congestion requires the continuous incoming traffic flow with high flow.When the incoming traffic flow fluctuates regularly,the congestion will form a mobile synchronous flow and dissipate by itself.Through VISSIM,this paper simulates the traffic flow state of the same road section under different flows,The simulation results show that the regular fluctuation of on ramp merging traffic flow will indeed reduce the disturbance of merging traffic flow to the main road.Secondly,based on the track data,the lane changing behavior and car following behavior of vehicles are studied,and the correlation between micro behavior and macro state is analyzed by using the analysis results of micro indicators and macro parameters.By calculating the impact of car following and lane changing behavior on road capacity respectively,it is proved that car following behavior under congestion can also aggravate or spread congestion.Combined with the driver’s behavior model,this paper explains the phenomenon of sudden drop of traffic capacity based on three-phase traffic flow,and puts forward the reason hypothesis of sudden drop of traffic capacity caused by car following behavior.Finally,it is found that the improved social force model of Delpiano has poor fitting effect on the data in the state of congestion.Therefore,referring to the formula structure of gravity model,the social force model is improved and verified with real data.