Certain physiological and mental changes occur in the driver which collectively constitute driver fatigue. The present investigation was designed to determine the effects of fatigue on several performance tasks required in the operation of a driving simulator to support the view that driver fatigue results in a performance decrement. Sixty male subjects /paid undergraduates, average age 19/ were randomly assigned to one of six experimental conditions and were tested in a driving device patterned after the AAA device. Measures of tracking error, speed maintenance, and reaction time were obtained for each subject. Test sessions involved either 4 or 6 hours. Performance decrements were obtained in the tracking task for subjects in several conditions. The most obvious decrements occurred under the 6 hour conditions where performance during the first hour was significantly better than that shown during the last hour. In speed maintenance task, performance during the first hour also tended to be superior to performance during the last hour. Subjects who operated the device for the entire 6 hour period and performed all tasks during the session showed a decrease in reaction time during the driving sessions. In each condition the reaction time was faster during the last hour than during the first hour of the task. The results suggest that subjects adjust their effort to the expected duration of the task, since subjects in the long sessions did not perform as well as subjects in the shorter conditions during the initial periods.
Abstract