Drivers’ perception and awareness of delay at traffic signals with countdown timers

The time spent at signalised intersections significantly influences route choice decisions, with perceived time often outweighing actual time in drivers’ decision making. While psychological and behavioural studies suggest limited user awareness of temporal changes, empirical evidence in transportation remains scarce. This study examines how drivers perceive and report stop times at signalised intersections and assesses their sensitivity to variations in delay. In addition, it explores how different signal displays – conventional signal devices (CSD), hourglass displays (HD), and continuous countdown timers (CCT) – shape drivers' time perception. Data were collected through roadside interviews and field measurements at three intersections in Iran. Findings indicate that while drivers often overlook minor differences in stop times, they correctly discern broader trends. Notably, time reporting was more consistent among drivers exposed to CCTs, where stop times were under-reported by approximately 20%. In contrast, HD and CSD led to over-reporting by about 15%. The results highlight CCT’s superiority in improving time awareness and reporting accuracy compared to HD and CSD. These insights underscore the importance of signal display design in shaping driver perception and suggest that countdown timers could enhance traffic management strategies by aligning perceived and actual stop times more effectively.