Research On Traffic Characteristics Of Interchange Area At Ramp Exit Of Urban Expressway

With China’s accelerated urbanization process and the fast-growing construction of traffic infrastructure,urban expressway developed rapidly in large and medium-sized cities in China,and has become an main transportation stems that connect various regions of the city in recent years.Due to the different directions of the traffic flow,the exit area of the ramp forms a traffic conflict area which is called interweaving area in the system of urban expressway,Traffic conflicts at the interweaving area of the ramp exit directly lead to slow traffic flow,even traffic jams or traffic accidents.Traffic congestion often tracks back to the main road along the upstream of the traffic flow direction and then seriously affects the high-efficiency operation of the expressway.It is significant in both theory and practice to conduct further research on the traffic operating conditions and traffic stream characteristics in the interlaced area of the expressway ramp exit.The research results can provide theoretical basis and method reference for the management and control of the expressway system.The paper fully demonstrates the operating point of the expressway and the existing problems,and chooses ramp export downstream connection and expressway on-ramp mixed signal control intersection area as the research object.A comprehensive summary of the current is carried from three aspects of traffic fluidity,conflict characteristics,and traffic capacity characteristics.The specific research content is as follows:First of all,on the basis of the demonstration of the composition and types of the interweaving area of expressways and the measured data of the eastern and southern expressways in Changchun,the five-minute statistical interval is also used.The paper has analyzed the statistical characteristics of traffic flow density and interweaving flow in different interweaving areas by contrast.And it is proposed that the interleaving flow ratio is one of the main parameters to characterize the characteristics of the interleaving region.What’s more,the paper compares and analyzes the conflict characteristics of the interweaving area of the ramp exit of the expressway in the east and south of Changchun City,establishes a quantitative relationship model between traffic flow,traffic density,interweaving flow and the number of conflicts,and analyzes its characteristic values based on this.Eventually,aiming at the interwoven area with large interwoven flow and under the premise of traffic conflicts in the interwoven area,use the analytic hierarchy process(AHP)to determine the weight of the factors affecting the capacity of the interwoven area.Furthermore,the influence factors are weighted by MATLAB programming,and the weight of the influence factors is sorted.By doing this,three main factors affecting the capacity of interwoven zone are obtained.In addition,based on the measured data of Changchun City,the conflict correction coefficient is calibrated and verified,and the optimized capacity calculation model is compared with the "Ninth Five-Year Guide Algorithm","Tenth Five-Year Plan Algorithm" and "China Highway Capacity Manual" algorithm to verify its superiority.