The Comparison between Visual Distraction and Cognitive Distraction

Many incidents and crashes can be attributed to driver distraction, due to increasing use of in-vehicle information systems (IVISs). Although visual and cognitive distraction has been studied extensively, relatively little research has compared the differences of effects between them on driving performance in the field. To fill this gap, twelve participants drove on roads under three distraction conditions: without distraction, with visual distraction, with cognitive distraction. Results revealed that visual distraction leads to higher speed variance and resulted in higher workload. Cognitive distraction made steering less smooth, but improved lane maintenance. Visual distraction was associated with more off-road glances, while increased blink frequency was observed during cognitive distraction. Both distractions caused gaze concentration and slow saccades when drivers looked at the roadway. Overall, visual distraction interferes with driving performance more than cognitive distraction, but they influence vehicle control and gaze behavior in different ways. These results suggest that minimizing visual demand is particularly important in the design of in-vehicle systems and also will be beneficial for the development of distraction countermeasures.