Comparative analysis of driver's brake perception-reaction time at signalized intersections with and without...

Area of Science:

• Traffic Engineering
• Human Factors
• Transportation Safety

Background:

• Countdown timers aim to inform drivers of signal phase changes.
• Limited research exists on the impact of countdown timers on driver brake perception-reaction time (BPRT) to yellow traffic signals.
• Understanding BPRT is crucial for traffic safety at signalized intersections.

Purpose of the Study:

• To characterize and model driver's BPRT to yellow signals with and without countdown timers.
• To identify factors influencing BPRT in the presence and absence of countdown timers.
• To evaluate the safety implications of countdown timers on driver behavior.

Main Methods:

• On-site observation of "first-to-stop" vehicles at six signalized intersections in Harbin, China.
• Collection of BPRT data following yellow light onset within the transitional zone.
• Statistical analysis using Log-logistic and Weibull distributions, and accelerated failure time (AFT) duration models.

Main Results:

• BPRT distributions differed significantly with and without countdown timers (Log-logistic vs. Weibull).
• Key factors influencing BPRT included yellow-onset distance, approach speed, and deceleration rate.
• Countdown timers appeared to impair BPRT, particularly at greater distances and higher deceleration rates, potentially leading to risky behaviors.

Conclusions:

• Countdown timers may not always enhance traffic safety and can negatively affect driver BPRT.
• Driver BPRT is influenced by intersection geometry, speed, and deceleration, with timer effects varying based on these factors.
• The study highlights a potential weakness of countdown timers, suggesting a need for re-evaluation in traffic safety design.