Least Expected Time Paths in Stochastic Schedule-Based Transit Networks

Dang Khoa Vo,Nguyen Huynh Tuong,Tran Vu Pham,Van Hoai Tran

doi:10.1155/2016/7609572

Abstract

We consider the problem of determining a least expected time (LET) path that minimizes the number of transfers and the expected total travel time in a stochastic schedule-based transit network. A time-dependent model is proposed to represent the stochastic transit network where vehicle arrival times are fully stochastically correlated. An exact label-correcting algorithm is developed, based on a proposed dominance condition by which Bellman’s principle of optimality is valid. Experimental results, which are conducted on the Ho Chi Minh City bus network, show that the running time of the proposed algorithm is suitable for real-time operation, and the resulting LET paths are robust against uncertainty, such as unknown traffic scenarios.

Highlights

The routing problem in a schedule-based transit network involves scheduling decisions made by a traveler, for example, accessing to a stop, walking between stops, waiting to board, traveling in-vehicle, alighting, and egressing
This issue is related to the question of how to incorporate the correlation of vehicle arrival times into the routing process, in which constraints on transit routes and constraints on vehicle arrival times are taken into account: (i) A time-dependent model is proposed for stochastic schedule-based transit networks where the correlation of all vehicle arrival times is presented as a scenario
To give an overview of least expected time (LET) paths found in the experiments, we first examine the impact of different sets of scenarios on LET o-d paths

Summary

Introduction

The routing problem in a schedule-based transit network involves scheduling decisions made by a traveler, for example, accessing to a stop (station), walking between stops, waiting to board, traveling in-vehicle, alighting, and egressing. These decisions guide the traveler from an origin to a destination with minimum travel costs, such as number of transfers, total travel time, walking time, and waiting time. The main issue when designing a routing algorithm in a schedule-based transit network with correlated vehicle arrival times is to model the stochastic correlation of vehicle arrival times. This issue is related to the question of how to incorporate the correlation of vehicle arrival times into the routing process, in which constraints on transit routes and constraints on vehicle arrival times are taken into account:

Objectives

Methods

Results

Conclusion