Abstract
Flood damage to road networks primarily manifests as a loss of transportation functionality. Current analyses of road network functionality loss during floods are based on specific flood scenarios. This study analyses flood risk to road networks by assessing the probability of stability loss for various vehicle types (SUVs/emergency vehicles, and cars). Eventually, a flood risk map of the road network is generated. The flood risk of each road is computed as reduced accessibility, measured in this paper via isochrones. Bristol (UK) is used as the case study area, with all hospitals as starting points to study the coverage area of emergency vehicles within a given time frame. The results indicate that road network functionality for SUVs/emergency vehicles has a lower flood risk than that for cars. Additionally, the city centre of Bristol exhibits a higher flood risk, hindering emergency medical vehicles from reaching high-risk flood areas. The findings of this research offer strategies to mitigate the impact of floods on road networks and prepare emergency medical services before flood disasters occur. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11069-026-08005-z.