A multi-perspective functionality loss assessment of coupled railway and airline systems under extreme events

The coupled national-scale railway and airline systems (CRASs) have drastically improved inter-city connectivity and national economics, but they remain susceptible to various extreme events. These events, including flooding and typhoon, often manifest as localized events because all direct interrupted components lie in a small region relative to the large-scale distribution of CRASs. Instead of the hazard-specific modeling of each localized event, this paper introduces four types of localized disruption models to simulate localized events with various locations, impact coverages, and time spans. A multi-perspective framework is then proposed for travel time-based functionality loss assessment of CRASs under localized events. Taking CRASs in China as an application, results demonstrate that (1) the functionality loss is highly sensitive to the event location, and events in areas with more population, higher GDP, and larger transport systems tend to cause higher functionality loss; (2) the impact coverage of events has a limited influence on functionality loss, as critical areas identified under circle-shaped impact coverage keep consistent with those under administrative district-based coverage; (3) the functionality loss and critical areas vary largely with the time span of localized events. The findings provide valuable insights in devising mitigation strategies for CRASs against various extreme events.