Young drivers are most likely to have sleep-related crashes.

So who is most at risk when it comes to drowsy driving?  In general, any driver who doesn't get enough sleep can fall victim to fatigue or be at higher risk for experiencing a decrease in alertness.

But according to the National Sleep Foundation, certain groups are more likely to have fall-asleep crashes.  They include young males, shift wokers, commercial drivers and people with untreated sleep disorders.

A study by the National Highway Traffic Safety Administration and the State of New York found that young drivers are more than 4 times more likely to have sleep-related crashes than are drivers over age 30.

According to the National Sleep Foundation, shift workers and people who work long hours fall into the high-risk category because the human body never fully adjusts to shift work.  The body's sleep cycles are dictated by light and dark cycles, and generally lead one to fell sleepy between midnight and 6 a.m.  For more on at-risk groups and sleep strategies for shift workers, check out the links on the left side of the page.