Roussou S., Ziakopoulos A., Ventura R., Yannis G., “When the Lights Go Out: Observing Pedestrian and Driver Behavior During a Traffic Signal Failure in Central Athens”, Proceedings of the the 17th World Conference on Transport Research (WCTR), Toulouse, France, 6-10 July 2026.

This paper examines how urban road users behave when a traffic light stops working. The study use data derived from a one-hour video recording from a central intersection in Athens, where both pedestrians and drivers had to use the street without any signal control. When the signal failed, traffic flow did not stop, but it was pedestrians who hesitated or waited for long periods before attempting to cross and taking opportunities only when traffic slowed or a small gap appeared. Vehicle phases were generally longer and more irregular, while pedestrian crossings were shorter. Groups that included elderly individuals waited longer and crossed more cautiously, whereas younger groups tended to move faster and accept smaller time gaps between vehicles. This reflects how people make quick safety judgments and how these decisions often emerge collectively within a group. Throughout both the observation period and the automated video analysis, behavioral patterns remained consistent. These findings demonstrate the ability of the pedestrians to manage to cross, but the situation was far from efficient or safe. Long waiting times and uncertainty highlight the need for reliable backup or adaptive systems that can take over when signals fail.