Exploring vulnerability bottlenecks of large-scale bus transit networks based on topological dynamics

With the emerging interdisciplinary study between transportation and network topological dynamics, exploring vulnerability bottlenecks (which consider knowledge differences between infrastructure disruptions and route service disruptions) of large-scale bus transit networks has become prevailing. This study aims to distinguish and simulate two types of disruptions by considering different concerns of different stakeholders on vulnerability. An integrated vulnerability evaluation indicator is designed to realize the comparability of attacks at various scales (which include single target, route, and area scales) and the diversity of measuring perspectives. Then, a case study is conducted based on the designed attack strategy set, from which the most efficient deliberate attack to trigger network vulnerability is quantitatively explored. The results indicate that the areas of the large-scale bus transit network accessing and interacting with urban rail transit stations are vulnerability bottlenecks, and the destructiveness of a failure edge is driven by the scale of sudden failures it constitutes. This work deepens the understanding of two types of disruptions, improves the comparability of various vulnerability studies, and provides insights for formulating operational management policies.