The Commercial Motor Vehicle (CMV) Driver Fatigue and Alertness Study was the largest and most comprehensive over-the-road study of its kind ever conducted in North America. Its primary purposes were to establish measurable relationships between CMV driver activities and physiological and psychological indicators of fatigue and reduced alertness and to provide a scientifically valid basis to determine the potential for revisiting the 60-year-old hours-of-service regulations. A number of work-related factors thought to influence the development of fatigue, loss of alertness and degraded performance in CMV drivers was studied within an operational setting of real-life, revenue-generating trips. These included: the amount of time spent driving during a work period; the number of consecutive days of driving; the time of day when driving took place; and schedule regularity. It was found that the strongest and most consistent factor influencing driver fatigue and alertness was time-of-day; drowsiness, as observed in video recordings of the driver's face, was markedly greater during night driving than during daytime driving. The number of hours of driving (time-on-task) was not a strong or consistent predictor of observed fatigue. Other study findings noted that the number of driving periods was not a strong or consistent fatigue predictor; that there was a low correlation between drivers' subjective self-ratings of alertness/sleepiness and concurrent objective performance measures; and that there was a large difference between the mount of sleep drivers reported as their "ideal" and the amount they obtained during principal sleep periods in the study setting. While there is no single solution to the fatigue problem, much can be done to address driver fatigue through a combination of innovative hours-of-service regulation and enforcement, education, driver work scheduling, innovative fatigue management programs, driver screening, fitness for duty and alertness monitoring systems, and additional research. (A)
Abstract