Exploring the Influence of Signal Countdown Timers on Driver Behavior: An Analysis of Pedestrian–Vehicle Conflicts at Signalized Intersections

Das, Subasish · 2023 · Transportation Research Record Journal of the Transportation Research Board

DOI: 10.1177/03611981231186987

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Summary

This study investigates the impact of signal countdown timers (SCTs) on driver behavior, specifically focusing on pedestrian–vehicle conflicts at signalized intersections. While SCTs are widely implemented to improve intersection capacity and reduce driver anxiety, their influence on safety-critical behaviors, particularly during the final seconds of green phases, remains under-researched. The authors hypothesize that the critical timing of SCTs may induce risky driver actions, such as errors and violations, thereby increasing the potential for accidents involving pedestrians. The research employed a dual-method approach using data from Babol, Iran. First, an on-road questionnaire survey was conducted with 369 drivers to assess self-reported behaviors. The survey utilized a six-point Likert scale to evaluate four categories of driving faults: lapses, errors, unintentional violations, and intentional violations. Factor analysis was performed to identify latent factors influencing driver responses. Second, a naturalistic driving study (NDS) was conducted with 28 participants equipped with in-vehicle cameras and sensors. Researchers analyzed video recordings from two high-traffic intersections to identify vehicle–pedestrian conflicts, defined as changes in movement or direction to avoid collision. From 303 interactions, 117 conflict cases were identified and coded for variables including vehicle speed, distance to pedestrians, driver age, and specific actions taken (e.g., acceleration, lane changing, braking). The results indicate that SCTs significantly influence driving behavior, particularly during the final seconds of the green light. Factor analysis of the questionnaire data revealed that driving errors and intentional violations were the most significant factors affecting driver behavior, whereas lapses and unintentional violations had lesser impacts. Drivers reported behaviors such as overtaking aggressively, failing to check for pedestrians, and becoming distracted by the timer. The NDS data confirmed that the majority of driver reactions occurred within the final 10 seconds of the SCT cycle. Common risky actions included increasing speed, changing lanes, and simultaneous acceleration and lane changes. Binary and multinomial logistic regression models demonstrated that vehicle speed, distance to pedestrian crossings, and driver age were significant predictors of these conflict-inducing actions. The study concludes that SCTs act as an external factor that can provoke risky driver behavior, including errors and intentional violations, which may heighten the risk of pedestrian accidents. The findings suggest that while SCTs may improve traffic flow efficiency, they require careful consideration regarding safety implications. The authors imply that understanding these behavioral shifts is crucial for optimizing SCT application and improving intersection safety design.

Key finding

The presence of signal countdown timers significantly influences driver behavior during the final seconds of green lights, leading to risky actions such as speeding and lane changes that increase the potential for pedestrian-vehicle conflicts.

Methodology

mixed_methods

Sample size: 397

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enrich success semantic_scholar 2 2026-06-04
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