When Floods Hit the Road: Resilience to Flood-Related Traffic Disruption in the San Francisco Bay Area and Beyond

 As sea levels rise, urban traffic networks in low-lying coastal areas face increasing risks of flood disruption. Flood-related road closures cause employee absences and travel-time delays, creating cascading socio-economic impacts to individuals and businesses. The San Francisco Bay Area, known for its high levels of traffic congestion, has many major traffic corridors such as US-101 that run close to the Bay, thus exposing them to extreme flood events. Our goal is to quantify the potential traffic disruption caused in the San Francisco Bay Area by near-future sea level rise and flooding.

We integrate a traffic model with flood maps to simulate traffic patterns and estimate employee absences and travel time delays. Our results for the San Francisco Bay Area show that employee absences are mostly limited to the homes and workplaces within the flood zone, while travel-time delays propagate far inland as a result of the interconnectedness of the road network. The spatially extended nature of flood-related travel-time delays highlights that sea level rise and flooding have broad regional impacts. Our work thus highlights the need for a coordinated response from local governments, both near the Bay coastline as well as far inland, to address near-future flood-related traffic disruption.