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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 resilien...
Contexts in source publication
Context 1
... the COVID-19 crisis, an average of 1.4 million daily trips were made on a typical business day on the subway network operated by TTC in 2018 (12). In fact, certain segments of Line 1 (yellow line), shown in Figure 1, run with demand levels above capacity during morning peak. In such conditions, any disruption of the service cause severe delays to passengers and substantial economic losses. ...
Context 2
... network has a substantial fleet of 1,926 buses, 249 streetcars, and 868 trains (30). Figure 1 shows the rail network. The Yellow line runs north-south and is known as Line 1. ...
Context 3
... a result, similar incidents are expected to have extensive delays, despite deploying a good bus bridging plan. The analysis based on the total user delay is shown in Figure 10 and the associated clusters with the final subgroups are highlighted in red. ...
Context 4
... the context of the above discussion, incidents could be placed on a severity scale based on their effect on the system with regard to the total users' delay. Figure 11 illustrates the severity scale of unplanned closures having different characteristics. ...
Context 5
... performance This analysis is done using the five incidents described in Table 1, where each incident belongs to one category and is placed on the severity scale. The blue line in Figure 12 shows the TUD of the optimal plans generated using the bus bridging optimization tool developed by Itani et al. (7) at different durations, while the orange line presents the TUD of the non-optimal plan estimated using the bus bridging assessment tool presented in Aboudina et al. (9). The closure between SheppardYonge and Don Mills Station (Line 4) belongs to the least severe category since the line serves an uncongested corridor. ...
Context 6
... time variation shows that the optimal plan remains valid for different incident durations. On the other hand, the closures between Woodbine-Kennedy and Bloor-Eglinton designate medium to highly congested segments; however, the optimal plan does not remain optimal if the closure lasts for longer, as shown in Figure 12. This is because as the incident extends, more buses are needed. ...
Citations
... 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]. ...
Regarding tools and systems from artificial intelligence (AI), chat-based ones from the area of generative AI have become a major focus regarding media coverage. ChatGPT and occasionally other systems (such as those from Microsoft and Google) are discussed with hundreds if not thousands of academic papers as well as newspaper articles. While various areas have considerably gone into this discussion, transportation and logistics has not yet come that far. In this paper, we explore the use of generative AI tools within this domain. More specifically, we focus on a topic related to sustainable passenger transportation, that is, the handling of disturbances in public transport when it comes to bus bunching and bus bridging. The first of these concepts is related to analyzing situations where we observe two or more buses of the same line following close to each other without being planned deliberately and the second is related to the case where buses are used to replace broken connections in other systems, such as subways. Generative AI tools seem to be able to provide meaningful entries and a lot of food for thought while the academic use may still be classified as limited.
... 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. ...
While the trend towards building resilience in infrastructure systems for disaster risk reduction is accelerating, the application of infrastructure resilience is largely conceptual or an embellishment to established modelling techniques. In response, this paper sets out the theoretical foundations of infrastructure resilience, which broadly applies across critical infrastructure networks. This is followed by reviewing system-based and network-based approaches to resilience assessment with a focus on transport infrastructure, where there is an emerging body of studies. It spotlights critical issues in conflating resilience with other concepts of infrastructure safety management or merely tagging resilience on established methods, indicating a phenomenon of "old wine in new bottles". Also, oversimplifying disruption scenarios does not provide a sufficient basis for informed resilience planning. This paper reminds readers to look beyond resilience as a mere buzzword and offers guidance on how to do so by recognising the theoretical and methodological cornerstones of infrastructure resilience.
... In the research report of Integrated urban transport 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;Kennedy, 2010a, 2010b), emergency bus capacity and site selection (Teng and Xu., 2010;Gu et al., 2018) to introduce resilience enhancement in subway traffic. ...
Purpose
Resilience concepts in integrated urban transport refer to the performance of dealing with external shock and the ability to continue to provide transportation services of all modes. A robust transportation resilience is a goal in pursuing transportation sustainability. Under this specified context, while before the perturbations, robustness refers to the degree of the system’s capability of functioning according to its design specifications on integrated modes and routes, redundancy is the degree of duplication of traffic routes and alternative modes to maintain persistency of service in case of perturbations. While after the perturbations, resourcefulness refers to the capacity to identify operational problems in the system, prioritize interventions and mobilize necessary material/ human resources to recover all the routes and modes, rapidity is the speed of complete recovery of all modes and traffic routes in the urban area. These “4R” are the most critical components of urban integrated resilience.
Design/methodology/approach
The trends of transportation resilience's connotation, metrics and strategies are summarized from the literature. A framework is introduced on both qualitative characteristics and quantitative metrics of transportation resilience. Using both model-based and mode-free methodologies that measure resilience in attributes, topology and system performance provides a benchmark for evaluating the mechanism of resilience changes during the perturbation. Correspondingly, different pre-perturbation and post-perturbation strategies for enhancing resilience under multi-mode scenarios are reviewed and summarized.
Findings
Cyber-physic transportation system (CPS) is a more targeted solution to resilience issues in transportation. A well-designed CPS can be applied to improve transport resilience facing different perturbations. The CPS ensures the independence and integrity of every child element within each functional zone while reacting rapidly.
Originality/value
This paper provides a more comprehensive understanding of transportation resilience in terms of integrated urban transport. The fundamental characteristics and strategies for resilience are summarized and elaborated. As little research has shed light on the resilience concepts in integrated urban transport, the findings from this paper point out the development trend of a resilient transportation system for digital and data-driven management.
Rapid urbanization and growth of population in megacities generate severe pressures on urban rail transit (URT) system. The quantity and frequency of disruptive events have increased significantly, which might have obvious adverse impacts. A large number of passengers are stranded at disrupted URT station when a disruptive event occurs. One essential solution for passenger evacuation is the bus bridging service. This paper is aimed at addressing the passenger evacuation problem caused by a disruptive event in the URT network, by proposing a bus bridging service model considering the passengers’ space-time requirements. The model is proposed to minimize the waiting time of passengers and considers factors including bus service capacity limitations, bus stop parking capacity, and the maximum bridging time limit of a single bus. Buses are assumed to provide bridging service on either the local bus route or the direct bus route. The optimal routes and scheduling plans of bridging bus are designed. The model is applied to an example of a disruptive event in Shanghai URT line 9. The results of this example show that the proposed model is capable of reducing the waiting time of passengers and the number of buses used by 3.2% and 24.7%, compared with the traditional bus bridging service. Further analysis of the example shows that it is not a cost-effective solution to reserve a large number of buses for URT disruption. Decision-makers should comprehensively trade off between passengers’ space-time demands and monetary costs of bus bridging service.
