Emergency bus route optimization for passenger evacuation in response to metro disruptions

What the paper says

Metro systems serve as the backbone of urban public transit and play a critical role in sustaining daily urban mobility. However, unexpected events such as severe weather or equipment failures can partially disrupt metro services. Emergency bus services provide a timely and reliable alternative to disrupted metro segments, effectively mitigating their adverse impacts. This paper addresses emergency bus route design in response to metro disruptions. Unlike the traditional emergency bus routing strategy that provides point-to-point shuttle services between a disrupted station and a turnaround station, this study proposes a novel routing strategy that incorporates nearby transfer stations as additional evacuation endpoints, thereby effectively distributing passenger flows and alleviating congestion at turnaround stations during emergencies. To support this strategy, a multi-objective optimization model is developed to balance evacuation efficiency and passenger travel experience. Furthermore, to address the dynamic and uncertain nature of metro disruptions, a rolling horizon optimization method is introduced to dynamically adjust bus routes based on updated information, thereby enhancing the quality of bus routing decisions under uncertainty. The effectiveness and applicability of the proposed model are validated through a series of case studies. Results demonstrate that the proposed strategy outperforms the traditional strategy in reducing passenger delay. • Emergency bus routes are designed for passenger evacuation as a response to metro disruption. • An emergency bus routing strategy is proposed that incorporates transfer stations as additional evacuation endpoints. • A multi-objective optimization model is developed to balance evacuation efficiency and passenger travel experience. • A rolling horizon optimization approach is introduced to enhancing bus routing decisions under uncertainty.