How Closures of Bridges and Tunnels Affect Travel Time in New York City

Climate change has led to more frequent flooding of transportation network links because of sea level rise and extreme weather events, compromising mobility. In previous studies, we have identified bridge and tunnel approaches as critical infrastructure; inundation of these links reduces or eliminates capacity, causing queue spillbacks, rerouting, and increased travel times, with effects propagating through the network. This paper builds on previous work by integrating multi-modal demand, agent-based simulation, and strategic infrastructure prioritization under flooding scenarios. The case study examines the New York City transportation network in the U.S., analyzing commuter responses to potential closures of combinations of bridges and tunnels because of flooding, focusing on impacts on mobility and mode choice. Disruption scenarios are designed using historical data and risk maps to reflect realistic flood-induced closures, though without explicit hydrodynamic modeling. Spatial integration of flood data defines precincts, aligning travel demand analysis with vulnerability zones. Results indicate a significant impact on mobility from the closure of the Manhattan Bridge for morning commuters traveling from Brooklyn to Manhattan, while the Carey Tunnel’s closure has a relatively minor effect. Mode choice is significantly affected when public-transit-carrying links are disrupted. These findings demonstrate the critical need to prioritize multimodal link protection in urban resilience planning.