Effect of External Distractions

Abstract

Distractions are a major contributor to automobile crashes, almost one-third of which are thought to be caused by distractions external to the vehicle. Increasingly, external distractions include video billboards, marquees, and variable message signs placed above and beside the highway. It is known that distractions outside the vehicle, especially video billboards, have effects on various vehicle control measures, such as the minimum headway distance to a braking lead vehicle, and that novice drivers and experienced drivers spend equally long times looking at distractions outside the vehicle. In contrast, experienced drivers are much less likely than novice drivers to take long glances at distractions inside the vehicle. This finding raises two questions. First, why are experienced drivers taking such long glances at an external distraction when they are not willing do so when a secondary task arises inside the vehicle? Second, if experienced drivers are sacrificing some of their ability to monitor visible hazards in the roadway ahead, are they sacrificing even more of their ability to anticipate unseen hazards? An experiment to evaluate these two questions had novice and experienced drivers perform an external search task (similar to reading a digital billboard) while driving in a simulator. Monitored throughout were eye movements of the participants and measures of the vehicle, such as lane position and speed. The major finding was that the long glances of both experienced and novice drivers came at the cost of identifying potential hidden hazards and seeing exposed moving threats.