Transport networks constantly evolve due to planned modifications or unforeseen events. While these occurrences are inconvenient for road users, they typically allow people to plan and adjust their travel in advance. But what happens when a major bridge collapses overnight? This scenario unfolded in Dresden, Germany, in September 2024, presenting an unexpected challenge to the city’s transport system and especially cyclists.

Based on the analysis of GPS track data collected before, immediately after, and up to two weeks following the collapse, we assessed changes in bicycle traffic volume patterns. Additionally, we identified shifts in route choice and quantified the extra effort in terms of travel time and distance for the most popular origin-destination relations. We also examined the trade-offs cyclists were forced to make in terms of waiting times, the number of waiting events, and safety. Furthermore, we analyzed individual-level adjustment patterns, shedding light on how cyclists adapted right after the collapse. Two additional data sources – a survey and public transport data – facilitated a more detailed analysis of bridge use, substitution patterns, and the identification of critical areas within the city that may require further interventions by authorities.

Initial results reveal that travel times increased and departure times became more variable. Cyclists demonstrated remarkable adaptability, utilizing alternative routes and adjusting their travel times accordingly.

The impact of the collapse on cyclists' mobility behavior will provide valuable insights into the key interventions needed to enhance the resilience of cycling networks which ultimately also promote a long-term shift toward cycling.