Assessing the Bus Bridging Effectiveness on the Operational Resilience of the Subway Service in Toronto

Abstract

Unplanned rail disruptions result in substantial delays to passengers and severe effects on the economy of a large city like Toronto. While bus bridging has been a widely adopted method to replace the subway service in such events, its effect on the operational resilience of the subway service is less often studied. This study assesses the resilience of the subway network of Toronto employing an optimal bus bridging strategy. First, subway incidents are categorized based on their characteristics using K-mean clustering analysis. The incidents are then grouped based on the performance of optimal bus bridging plans. Classification and regression tree analysis is used for this task, employing two metrics: the total user delay and total number of shuttle buses under the optimal bridging scenario. Queueing and optimization models developed previously by the University of Toronto are used to determine and simulate the optimal bus bridging plans of a sample of incidents. The severity of unplanned disruptions is finally demonstrated using a severity scale and the effect of incident duration uncertainty is analyzed. The results show that along the congested city alignments, where the capacity of the roads and stations is limited, the bus bridging service is often insufficient to replace the train service. However, it could be a good alternative in uncongested subway segments where the available street capacity is relatively high, allowing large bus volumes to serve the corridor. This model is easily applicable to different rail systems and it could assess other systems to produce better bridging plans.

Bus Bunching and Bus Bridging: What Can We Learn from Generative AI Tools like ChatGPT?

“…Q: "What are some challenges or limitations of bus bridging?" Bing: "Some of the challenges or limitations of bus bridging are: Bus bridging may not be able to replace the train service adequately in congested city alignments, where the capacity of the roads and stations is limited [65].…”

“…Both answers are meaningful, even if they have a different twist. Specific references from Bing are meaningfully provided with the above text in this order: [49,64,65].…”

Old Wine in New Bottles? Understanding Infrastructure Resilience: Foundations, Assessment, and Limitations

“…In addition, another strategy to improve the resilience of a particular transport network is to integrate it with another transport mode and find the optimal bridging scenario to improve its resilience. This is typically applied in resilience assessment of metro-bus networks (Itani and Shalaby, 2021;Qi et al, 2021;Liu et al, 2022b;Ren et al, 2019;Jin et al, 2014). As explored by Jin et al (2014), the resilience of metro networks can be strengthened by locally integrating with bus services to maintain system performance during disruption.…”

Resilience concepts in integrated urban transport: a comprehensive review on multi-mode framework

“…In the research report of TRB (2007), it was proposed that in the response and evacuation stages and the repair and service restoration stages after rail transit emergencies, the linkage support role of ground public transport should be imported to empower. Researchers studied the design of bus-bridging routes (Kuah and Perl, 1988; Martins and Pato, 1998; Deng et al , 2018), the scheduling model (Kepaptsoglou and Karlaftis, 2009; Jin et al , 2016; Itani and Shalaby, 2021), position of interchange stations (Tang et al , 2021; Derrible and Kennedy, 2010a, 2010b), emergency bus capacity and site selection (Teng and Xu., 2010; Gu et al , 2018) to introduce resilience enhancement in subway traffic.…”

“…In the research report of TRB (2007), it was proposed that in the response and evacuation stages and the repair and service restoration stages after rail transit emergencies, the linkage support role of ground public transport should be imported to empower. Researchers studied the design of bus-bridging routes (Kuah and Perl, 1988; Martins and Pato, 1998; Deng et al , 2018), the scheduling model (Kepaptsoglou and Karlaftis, 2009; Jin et al , 2016; Itani and Shalaby, 2021), position of interchange stations (Tang et al , 2021; Derrible and Kennedy, 2010a, 2010b), emergency bus capacity and site selection (Teng and Xu., 2010; Gu et al , 2018) to introduce resilience enhancement in subway traffic. Current studies emphasized the research on the emergency connection of public transport in the case of subway operation failure, and the optimization objectives and constraints considered are different. Most of them focused on the emergency rescue of trapped passengers after the subway traffic operation was interrupted.…”