Short-term Impacts of Carola Bridge Collapse on Road Traffic

Abstract

Understanding the short-term impact of unexpected network disruptions is critical for resilient traffic management. This study analyzes traffic flow and pattern changes in Dresden following the Carola Bridge collapse on September 11, 2024, using aggregate traffic data. We employ a paired T-test comparing pre- and post-collapse traffic flows to identify the critical roads with large impacts among the alternative bridges, connectors, and main arteries of the urban network in Dresden. We find that traffic flow changes show clear proximity property, diminishing with increasing distance from the collapsed bridge. Moreover, traffic patterns during workdays on critical roads were analyzed using a rolling index called the Peak Hour Indicator (PHI), which integrates traffic flow and speed to evaluate conditions and detect peak hours. Post-collapse peak hours show an extended period, implying likely changes in departure times. The findings provide insights into the short-term response and resilience of the urban traffic network after disruptions.