Vulnerability Assessment of Transport Networks under Extreme Conditions

Abstract

Climate-related hazards, operational incidents, and extreme disruptive events are increasing the exposure of transport systems to localized and systemic failures. This paper proposes a framework for assessing the vulnerability of urban road networks to major breakdowns (such as accidents, flood-related disruptions, and extreme weather conditions). We use a static traffic assignment model here, while dynamic features will be investigated at a later stage. The approach distinguishes between local effects on individual links and broader systemic impacts transmitted through rerouting and network-wide congestion. We introduce a simple composite link vulnerability indicator to capture both congestion amplification and network resilience across different demand segments. The methodology is first applied in a large complex network in the city of Minneapolis with both arterials and freeways, while other urban areas will be investigated and compared. The article situates this framework within a broader reflection on resilience, demand and supply shocks, information regimes, and traveller adaptation under extreme conditions and partial information.