Abstract:Frequent extreme precipitation events pose severe threats to cities. Road network, as thefoundation of the urban transportation system, is crucial for disaster evacuation and post-disaster re-covery. Failure and interruptions in certain nodes or sections in the road network due to precipitationcan trigger a series of cascading effects, indirectly exacerbating the loss of life and property for urbanresidents. To accurately assess the cascading failures of urban road networks and their impacts underextreme precipitation events, the study integrated traffic status with extreme precipitation scenariosand further considered the chain reactions of cascading failures. Utilizing traffic status data from bothmorning and evening peak periods, as well as off-peak periods, along with Points of Interest (POI) da-ta for transportation, medical, and educational infrastructure, the study employed a "load-capacity"model to analyze the evolution process and results of these failures in urban road networks under ex-treme precipitation events. The results indicated that during the morning peak hours, 292 roads in Nanjing's Gulou District would fail and become interrupted under a 100-year return period extreme pre-cipitation event. In the cascading failure simulation, 88 road segments exhibited severe congestion.Compared to transportation and medical infrastructure, educational infrastructure services were mostaffected by extreme precipitation. Additionally, traffic flow significantly impacted the service areas ofall three types of infrastructure. The research enriches and advances the research framework for urbanroad networks under extreme disaster events and provides guidance for urban flood emergency re-sponse and planning during non-conventional rainstorms.
