The effect of restricted head and neck movement on driving performance was measured by decision time at simulated t-intersections. Little traffic safety and human factors literature concerning the performance of drivers with physical limitations was found. Most accidents involving drivers with diminished capacities occur at intersections; therefore, simulated t-intersections were selected for study. A laboratory study using a driving simulator was selected to provide better experimental control, safety, and repeatability. A fixed-basedriving simulator that incorporated video recordings of intersections to provide a 180-degree field of view was used. Eighteen intersections with various levels of traffic volume and sight distance were studied. The 72 test subjects were either between the ages of 30 and 50 or between 60 and 80, and half in each group had a restricted range of neck movement. The subjects' task was to depress the brake pedal, watch the video presentations of the t-intersections on three screens, and release the brake pedal when it was safe to make a left turn. The decision time was a measure of driving performance. The following hypotheses were confirmed: (a) decision time increases with age, and age effects dominated the other factors studied; (b) decision time increases with age and level of impairment, indicating that younger drivers are able to compensate for their impairments, but older drivers both with and without impairments are unable to make compensations in their driving performance; and (c) skewed intersections are hazardous for drivers with neck impairments. Further laboratory and field studies are recommended to validate the study results and to examine the problem of skewed intersections. This paper appears in Transportation Research Record No. 1281, Human Factors and Safety Research Related to Highway Design and Operation 1990.
Abstract