Research On The Accessibility Calculation And Optimization Method In The Last Train Period Of An Urban Rail Transit System

With the improvement of living standard,the travel demand of residents in the evening is also increasing.Due to its convenience and high punctuality,urban rail transit has become a popular public transportation mode for most residents.Since urban rail transit is not available all day,passengers travelling at night may miss the last train or need to change the mode of travel at the transfer station because of the departure of the last train.At present,the urban rail transit operators lack effective methods to provide passengers with relevant information on the availability of the last train period,and the timetable of the last trains on each line lacks coordination.It is difficult to meet the travel demands of more passengers.The key problems that need to be solved are how to measure the accessibility of urban rail transit and how to adjust and optimize the timetable of the last train to achieve better accessibility.In this paper,the reachability of urban rail transit and the optimization method of last train timetable considering maximum reachability are studied,and the time interval reachability optimization and query system of urban rail transit are developed.The specific work is as follows:(1)This paper analyzes the concrete meaning of the accessibility of urban rail transit under different conditions and defines the concept of the last train period.Then we analyze the main factors that affect the accessibility of the last train,and point out that how to measure the accessibility,how to optimize the last train schedule to achieve better accessibility,and how to show passengers the accessibility of the last train period of urban rail transit are the three important issues that need to be solved(2)Based on the fixed travel path,the concepts of the latest travel time and the farthest reachable station are proposed,and the problem is solved by the calculation method of the latest travel time and the farthest reachable station.In order to overcome the limitation of the fixed path algorithm,the reachability calculation method under the variable path condition is proposed.The improved Dijkstra algorithm is used to solve the space-time network model.An example is given to verify the accuracy of the reachability calculation method based on the variable path condition.it is proved to be better than that method based on the fixed path method.(3)From the point of view of the urban rail transit operation enterprises,considering the interests of the enterprises and the passenger travel needs,a multi-objective optimization model with the largest proportion of passengers and the earliest closing time of the last train is established.Beijing urban rail transit is selected as a case study and solved by non-dominated rapid sorting genetic algorithm with elite strategy.By analyzing the results of the solution,it is found that the Pareto optimal solution has a partial solution which can increase the proportion of the passenger flow and advance the closing time of the last train at the same time compared with the current last train timetable.(4)Based on the related theories and algorithms described in this paper,based on the background of urban rail transit in Beijing,this paper develops a system for the optimization and query of the time interval accessibility of the last bus of urban rail transit by using C#language.The automatic timing optimization of the last train timetable is realized.And from the point of view of passengers,the functions of the designated starting point and the end point query,the designated starting station query function and the designated line query function are realized.Make it easier for passengers to inquire about the accessibility of an OD and the shortest or farthest path in time and space,so as to provide guidance for passengers to travel.It makes up for the gap of the passenger-oriented urban rail transit last time interval access query and guidance system.