Flood-Induced Commute Disruption in the San Francisco Bay Area and Beyond

Abstract

As sea levels rise, urban traffic networks in low-lying coastal areas face an increasing risk offlood disruption and commute delays. We hypothesize that road network connectivity rather than flood exposure governs commute delays. We integrate an existing traffic model with flood maps to identify inundated roads, simulate traffic patterns, and quantify commute delays. When identifying inundated roads, we demonstrate potential biases arising from the model integration and propose appropriate refinements, such as incorporating road geometry and elevation data, and identifying small-scale topographical features like road-creek crossings. Our results for the San Francisco Bay Area show commute delays propagate far inland, creating longer commute delays for inland communities with low road network connectivity than for communities near the flood zone. We show that metric reach, a measure of road network connectivity, is a better proxy for quantifying the resilience of a community to flood-related commute delays than flood exposure.