Establishing closure criteria for coastal roadways under flooding conditions

The increasing frequency and intensity of floods pose major challenges for transport networks, particularly in coastal cities. In addition to serving as vital arteries for commuter traffic and freight movement, coastal roads form essential links in the urban transportation network, connecting communities, businesses, and critical services. This study presents a framework for assessing the impacts of flooding on transportation systems and establishing road closure criteria for coastal roads with urban connectivity importance. We integrate Delft3D-FM hydrodynamic modeling with empirical road closure data, geospatial analysis, and vehicle stability assessments to evaluate flood hazards and develop practical management criteria. The framework incorporates the effects of sea level rise and more extreme weather events, allowing for an assessment of changing flood hazards over time. Analysis of empirical closure records enables the development of four distinct flood severity thresholds based on depth of inundation. These thresholds incorporate both flood depth and velocity, providing a detailed hazard assessment that supports the development of road closure criteria to address the increasing challenges posed by flooding. Findings indicate that, without proactive adaptation measures, coastal roadways are likely to transition from episodic flooding to chronic inundation. This underscores the importance of adaptive design and operational management strategies to ensure safe and resilient transportation infrastructure.