Effect of Restriction of Vision on Driving Performance

Abstract

Experts estimate that vision provides 90 percent of the sensory input used by drivers to guide and control their vehicles. In a field study, investigators restricted vision to determine the effect on driving performance. Commonly occurring binocular visual-field defects were simulated for a group of young normal subjects and then their driving performance was assessed on a private closed rural road, free of other vehicles. The monocular condition did not significantly affect performance for any of the driving tasks assessed; however, restricting binocular vision had several effects. When binocular vision was 40 percent or less, the time to complete the course significantly increased, the ability to detect and correctly identify road signs decreased, and the ability to avoid obstacles and maneuver through limited space decreased. Accuracy of road positioning and reversing were also impaired. Some other driving tasks, such as driver's ability to estimate speed and stopping distance, were not affected by restriction of binocular visual fields. More definitive research on the interrelationship between visual performance and performance on the road is necessary.