An evaluation of a traffic signal with white bar strobe light

The best drivers occasionally overlook cues and make errors which sometimes result in traffic accidents. Therefore, the need to draw drivers attention to unexpected and/or difficult to perceive traffic signals is a concern to traffic engineers. The objective of this research was to study a traffic signal with a strobe light, and to determine the influence of the strobe, if any, on drawing drivers attention to a red signal indication. The measures of effectiveness selected for this study were vehicle deceleration rates, speed profiles, perception - reaction times, and violations of the red of the red indication.

Two data collection techniques were selected for this study. First, a 20-pen graphic recorder was used for data collection to allow the determination of deceleration rates, speed profiles, and violations. Secondly, a stop watch was used to measure drivers perception -reaction times. A before-and-after study was used to evaluate driver performance at a single signalized intersection approach. This study design negated the effects of site differences, and allowed a direct comparison of driver performance at the traffic signal with and without a strobe light. Statistical analyses were used to determine if differences determined between the before-and-after study were statistically significant.

This study concluded that the use of a strobe light at a difficult to discern traffic signal had an effect on driver's performance measures. The results show that driver perception- reaction time were lower. Indications are that drivers did apply their brakes earlier and made a safer and more gradual approach to the traffic signal. Furthermore, the maximum deceleration rate was reduced from an "undesirable level" to a "practical level" as defined by The Traffic Engineering Handbook. The point at which this decrease in deceleration rate occurred was located 100 feet upstream from the traffic light.

As a result of the limited sample size and the single location and approach, the results showed that future studies are warranted on the subject of strobes and their effect on driver's performance.