Driving Performance as a Function of Time on the Road *

Abstract

The effects of driving time were examined in two experiments, both involving two-hour drives. Experiment 1 used a fully instrumented vehicle on a closed course under nighttime conditions. Experiment 2 used an interactive driving simulator. In Experiment 1 effects of driving time were increases in the frequency of right-side lane departures, decreased speed, and increased speed variability, all consistent with decreased arousal associated with fatigue. Driving time effects in Experiment 2 included increased reaction time and reaction-time variability to signs as well increases in speed, lateral acceleration and in overall performance as reflected in pay, indicating compensation for the effects of fatigue. Differences between the experiments were examined as possible explanations for differences in results.