A recent study reports about the risk of lack of sleep on commercial drivers. In an article entitled "Impaired Performance in Commercial Drivers: Role of Sleep Apnea and Short Sleep Duration" researchers from the University of Pennsylvania "examined 406 truck drivers and found that those who routinely slept less than five hours a night were likely to fare poorly on tests designed to measure sleepiness, attention and reaction time, and steering ability. Drivers with severe sleep apnea, a medical condition that causes a poor quality of sleep, also were sleepy and had performance impairment," according to a summary of the article at Insurance Journal.
The Penn report indicates that 5600 people per year are killed in wrecks with commercial trucks and that many of them involve drivers falling asleep at the wheel.
The Penn report is published in American Journal of Respiratory and Critical Care Medicine. The article can be accessed here.