Studies have shown that sleep deprivation effects are the same as being drunk when you are driving. Apparently there was a study in Australia, and they tested 40 people to create a "blood alcohol equivalent" for different levels of sleep deprivation impairment.
After 24 hours without sleep, a subject had similar reaction problems as if they had 0.10 percent level of blood alcohol. Seventeen hours of sleep deprivation meant an equivalent of 0.05 % blood alcohol level of impairment.
The highest risk categories are obvious:
- Shift workers
- Commercial drivers (esp. long-haul truckers)
- Young mail drivers
- People with undiagnosed sleep disorders (insomnia, sleep apnea, narcolepsy, restless leg syndrome etc.)
- A study in North Carolina showed that 55% of fatigue-related crashes involved people under 35, and 78% were male. Statistics are probably vastly underreported on this issue of fatigue-related crashes.
There was a study of fatal crashes on the New York Thruway which showed that 40-50% of the crashes occurred when a driver fell asleep at the wheel.