Study On The Connection Technology Of Urban Elevated Expressway Exit Ramp And Ground Road

At present,At present,China's urbanization process has entered the stage of development of large urbanization and urban suburbanization,and the urban span has gradually increased.As an important part of the urban road network,the urban elevated expressway is the “big artery” of the urban road network.With the increasing traffic volume,the traffic congestion of the expressway exit ramp and the ground road junction is serious.When the congestion is serious,it will go back to the elevated road and affect the normal traffic of the main road of the elevated road.Therefore,this paper studies the connection technology of the expressway exit ramp and the ground road.According to the distance between the exit point of the elevated expressway exit and the downstream intersection,this paper divides the connection form of the exit ramp and the ground road into a near-intersection-type exit ramp and a section-type exit ramp.On the basis of field investigation of the traffic data of the two connecting sections,the traffic flow characteristics of the connecting section are analyzed,and the VISSIM simulation model of the connecting section is established.With the help of VISSIM simulation model,the influence of the length of interlaced area and the right turn ratio of ground roads on the capacity of the connecting section is analyzed.The calculation model of capacity reduction factor of the link section is established,which takes the length of the interlaced area and the right turn ratio of the ground road as independent variables.Through the analysis of the characteristics of the driving process in the connecting section of the vehicle,the calculation model of the forming length of the connecting section is established based on the theory of acceptable clearance,the theory of the probability distribution of the headway,and the theory of vehicle safety change.On the basis of the study of right-handed interwoven export ramps,the principles and steps of designing the traffic organization scheme of the connecting section are proposed.Combined with the capacity calculation model,a selection method of traffic organization scheme based on interlacing ratio is proposed.In view of the fact that there is no research on the section-type exit ramp connection scheme,this paper introduces the mandatory lane change rule based on the traditional cellular automata model,establishes the road segment-type exit ramp cellular automata simulation model,and analyzes the ground road and ramp.Using the simulation model,this paper analyzes the interaction between ground and ramp vehicles.In this paper,the calculation model of the additional lane length of the section exit ramp is established by using the accepted gap theory,the head time distribution theory and the vehicle safety lane changing theory.Considering the impact of vehicle re-entry on the normal traffic of the main roads on the ground,this paper analyzes the road conditions and traffic conditions of the road-type exit ramp connection scheme from two aspects of safe driving and traffic efficiency.This paper carries out the technology of connecting the elevated exit ramps to the ground roads from the micro level.The research results have certain significance for improving the traffic conditions of the export ramps and ground roads,and provide guidance for the reconstruction and new construction design.