Analysis Of Congestion Characteristics And Conflicts Of Metasteady Traffic Flow On Merging Areas Of Expressways

In recent years,there has been recurrent congestion during peak periods in the entrance ramp merge areas of expressways.The traffic disturbance generated by the traffic changing into the entrance ramp and the following vehicles is the key factor contributing to this congestion.This paper investigates the macroscopic characteristics and microscopic behaviors of such road sections using trajectory data.The main contents are as follows:Firstly,this paper selects a merging zone of the expressway that meets the requirements and uses vehicle trajectory data from UAV acquired by a target recognition tracking algorithm.The zonal observation model is combined to partition the data collection locations and analyze the traffic characteristics of the merge zone road sections.This paper proposes that the macroscopic demand of merging intensifies vehicle conflicts and generates congestion,which spreads upstream.Meanwhile,the traffic operation state smoothes out from the immediate downstream of the intertwined area,reflecting the gradual phenomenon that the closer to the downstream,the smaller the duration of potential conflict risk.Secondly,this paper uses the Time-to-Collision theory to calculate and analyze the microscopic characteristics under sub-steady traffic flow,comparing the microscopic characteristics before and after experiencing traffic oscillations.The spatial-temporal distribution characteristics of conflict points are constructed,and their correlation effects on following chases during acceleration and deceleration are analyzed.Based on the PET model,the characteristics of lane change behavior on traffic conflict changes are quantitatively analyzed to reveal the mechanism of sub-stable traffic conflict formation.This paper found that at the microscopic level,differences exist between vehicles and trajectories following the Newell model when making decisions.Finally,this paper proposes a control method based on the relationship between lane change behavior and traffic conflict in the merging area under sub-steady traffic flow.The parameters of the model are calibrated using macroscopic traffic flow characteristics,and the effect of the control method on traffic conflict and traffic delay is verified through simulation.This paper proposes an effective method to reduce traffic conflict.