Passenger trip planning in urban rail transit based on time geography

Passenger´s trip is influenced by not only space constraints, but also time budget due to the operation characteristics of urban rail transit (URT). Time variation can cause such problems that some planned paths are impractical for not coordinating with the last trains on schedule, seriously affecting rail passenger´s trip. A passenger´s travel path generation algorithm is proposed to solve the problem under both space and time constraints. It is developed on the basis of train search algorithm for URT and space-time prism, the core of time geography. By searching the Train Time-space Diagram forwardly from origin and then backwardly from destination, passenger´s accessible region and passing region could be obtained. Then a set of admissible paths is calculated from the intersection of those regions. It can be used for passenger trip planning in URT. Finally, Shanghai Metro is taken as an example to illustrate the effectiveness of the algorithm.