Research On Problem Of Efficient Paths For Urban Rail Transit

With the accelerating pace in urban rail transit construction, the expanding scale as well as improving structure in line network, the coupling coefficient of rail transit network is getting higher and different transfer between stations is more frequent. Therefore, it is the inevitable result of network development that we adopt the operation mode of seamless transfer. At the same time, due to the diversity of the route choice resulting from the cost of travel people think, it leads that it is difficult to grasp the transit path of passengers. So, it's particularly important to determine the travel path set by deeply analyzing the influencing factors effect to the path choice of passengers. So only by getting hold of the passengers'behaviors of route choice, we can accurately grasp the rules and paths, which can provide the basis and support for passenger flow forecast in urban rail transit and operation organization management as well as ticket clearing problem between operation business.In this paper, based on the passenger' behaviors in rail transit, we fully consider the influencing factors effect to the path choice about passengers and expand the general cost function. We redefine the efficient path which transfer time has been considered as a limiting condition and design the algorithm. The contents and conclusion of this paper are summarized as follows:(1) This paper establishes the network topology structure of rail transit based on particularity of rail transit network, which process the transfer nodes according to the particularity of rail transit network. On the account of the network topology above, the relations between the basic elements in rail transit network is presented, including stations, sections, lines and association relations between them, which provide mathematical basis for solving the efficient path and storing every element in computer.(2) Considering the transfer comfort of transit, it improves the general cost function. Analyzing the principal influencial factors of path choice provides premise for confirming the scope of efficient paths. Because the cost function of transfer is sensitive for passengers, transfer time has been considered as a limiting condition and the efficient path is redefined, which reduces the travel routes inconsistent with actual.(3) In view of the redefined efficient paths, we design path algorithm by using BFS. Since BFS is a path enumeration algorithm with inefficiency, the BFS algorithm that using key nodes determine the efficient path on the basis of features of rail transit network is presented. Furthermore, simple analysis of the path searching process proves the feasibility of algorithm and verifies that the modified algorithm does not only improve operating efficiency, but also save storage space.(4) Beacuse of different understanding about cost of different passengers attributes, the paper analyzes the paths based on various parameters, the conclusion demonstrate that transfer times restriction make the efficient paths more consistent with real data. Moreover, by solving the efficient path of OD pair, the generalal cost function considering transfer comfort is verified and the sensitivity analysis of the parameters is carried out. Simultaneously, we compares transfer flow of calculated results with the real date, which shows that transfer comfort will become a major factor that influences the route choice.