Passenger Flow Assignment Method Considering Capacity Limitation In Metro Network

With the country’s massive investment in subway construction and the superiority of the subway itself,more and more travelers choose to take the subway,and subway congestion has become a common phenomenon.Because the subway adopts the "one-ticket" seamless transfer operation mode,Operating units cannot directly obtain the distribution of passengers in time and space.Therefore,in order to improve the level of urban subway management and operation,it is extremely important to study the characteristics of passenger route selection and passenger flow distribution methods in the urban subway network.The research focus of this paper is the passenger flow distribution method in the time-space expansion network.Through the questionnaire survey of subway passengers,the factors and related laws that affect the route choice of passengers during the peak period are analyzed and the generalized route cost function considering capacity limitation is constructed.Based on this,an allocation model and solution algorithm are proposed.Use examples to verify the effectiveness and feasibility of the entire distribution method.Specifically,this article has carried out the following work content:(1)The constituent elements of the time-space expansion network and the specific steps for constructing the expansion network based on the timetable are given.Three common algorithms for searching effective paths are described,and their advantages and disadvantages are compared.Finally,a k-short-circuit search algorithm based on the extended network of timetables is proposed.(2)In order to more accurately obtain the basis for passengers to choose the travel route,and provide basic data for the parameter estimation to be carried out later,collect information on the operation of Xi’an Metro,design the Xi’an Metro questionnaire,and conduct a field survey.Statistics and analysis of the acquired data.The results show that during the peak period,the degree of congestion and the convenience of transfer are the factors that passengers are most concerned about when choosing a travel route.In addition,there are other factors such as psychological feelings,which provide directions for the next step in building a generalized route cost function.(3)After processing and analyzing the results of the questionnaire,this paper considers the train capacity limitation and the transfer capacity limitation of the transfer station.On this basis,the generalized path cost function is constructed,and the generalized path cost without considering the capacity limitation is also given.Function as a comparison.At the same time,a random balanced allocation model considering capacity constraints is established,and finally the model solving algorithm is introduced.(4)Based on the improved Logit model,the first two steps of the maximum likelihood estimation method are used to derive the parameter estimation formula of the model in this paper,which provides theoretical support for the parameter calibration in the following examples.(5)The calculation example is designed with the Xi’an subway as the background,and the final distribution result is used to verify whether the distribution method proposed in this paper is effective.The specific content includes: constructing the space network diagram of the OD pair,expanding the timetable on the basis of the space network to obtain the space-time network diagram,searching for effective paths in the space-time network diagram,using SPSS to calibrate the parameters of the model,and then Obtain the generalized path cost of the effective path,use the improved Logit model to find the probability of each path being selected,and obtain the final allocation result through the MSA algorithm,and then analyze and compare the allocation result with the actual survey result,including the sensitivity analysis of the parameters and the effective method Sexual analysis.