Hyperpath-based vehicle routing and scheduling method in time-varying networks for airport shuttle service

It is very significant for a reasonable vehicle routing and scheduling in city airport shuttle service to decrease operational costs and increase passenger satisfaction. Most of the existing reports for such problems assumed that the travel time was invariable. However, the ever-increasing traffic congestion often makes it variable. In this study, considering the time-varying networks, a vehicle routing and scheduling method is proposed, where the time-varying feature enables the traveler to select a direction among all the Pareto-optimal paths at each node in response to the knowledge of the time window demands. Such Pareto-optimal paths are referred to hyperpaths herein. To obtain the hyperpaths, an exact algorithm is designed in this study for addressing the bi-criteria shortest paths problem, where the travel time comes to be discontinuous time-varying. Given the techniques that generate all Pareto-optimal solutions exhibiting exponential worst-case computational complexity, embedded in the exact algorithm, a computationally efficient bound strategy is reported on the basis of passenger locations, pickup time windows and arrival time windows. As such, the vehicle routing and scheduling problem viewed as an arc selection model can be solved by a proposed heuristic algorithm combined with a dynamic programming method. A series of experiments by using the practical pickup data indicate that the proposed methods can obtain cost-saving schedules under the condition of time-varying travel times.