Measuring urban road network resilience to extreme events: an application for urban floods

Abstract

Designing and maintaining resilient transportation systems rely on identifying potential vulnerabilities and inefficiencies before crises occur. However, given the complexity of transportation networks, as well as the diversity of ways in which systems can fail, the problem of assessing the impacts of exceptional phenomena still lacks tools and metrics for analysis. Therefore, this paper aims to present a method for assessing the behavior of road networks during crises in which segments are disabled or unusable for a time. The method proposed was structured around two metrics calculated from the road network and trip distribution: network continuity and efficiency of alternative. With these metrics, we assess, as an example, the local and global impacts of various flooding scenarios in a case study at S\~ao Carlos, a medium-sized Brazilian city in the state of S\~ao Paulo. Our findings indicate that pedestrian movements are significantly less impacted than motorized vehicles by floods in the city, which may be due to the car-oriented nature of the avenues closest to rivers, and the shortest average length of pedestrian trips. These findings and metrics set a framework for further research involving other cities and natural phenomena to enrich the understanding of resilience in urban transportation networks.