Enhancing Safety Measures at Stop-Controlled Intersections: A Study on LED Backlit Signs and Drivers’ Behavior in Montréal, Québec

This study evaluates the safety impacts of upgrading traditional STOP signs to light-emitting diode (LED)-illuminated backlit STOP signs at urban intersections, aiming to address visibility and conspicuity concerns that affect driver behavior and intersection safety. STOP signs are critical for regulating traffic flow and minimizing conflicts, yet their effectiveness can diminish under low-visibility conditions. To assess the effectiveness of LED-enhanced signage, a before–after study was conducted using surrogate safety measures. Key performance indicators included vehicle speeds, driver compliance rates, and vehicle-to-vehicle interactions, recorded both prior to and following LED implementation. A multinomial logistic regression model was used to analyze driver behaviors, and a calibrated microscopic simulation model, optimized using a genetic algorithm (GA), was applied to estimate traffic conflict frequencies. Video data were processed to extract driver trajectories and reactions under varying signage conditions. Results showed LED STOP signs improved compliance rates from 60% to 85%, reduced average vehicle speeds by 25%, and increased post-encroachment times. Conflict analysis revealed significant reductions in vehicle-to-vehicle and pedestrian conflicts, particularly at night. These findings highlight the effectiveness of LED signage in enhancing intersection safety and offer important implications for urban traffic management and the adoption of advanced traffic control technologies.