The National Sleep Foundation has declared November 12-18, 2012 to be Drowsy Driving Prevention Week, in hopes of reducing the number of accidents related to sleep -- or, rather, lack of it.

More than 40 percent of Americans say they rarely or never get a good night's sleep -- and when they hit the road, that sleep deprivation can have serious repercussions.

Should you find yourself feeling sleepy behind the wheel, it's crucial to stop driving. The National Sleep Foundation highlights several warning signs that you're too drowsy to drive, including difficulty focusing, difficulty staving off daydreams, drifting from your lane, missing traffic signs, feeling restless or irritable and -- of course -- heavy eyelids or trouble keeping your head up.

Before long trips especially, make sure to get sufficient rest and remember to take regular breaks. Although most sleep experts often tell us to avoid caffeine close to bedtime, a couple cups of coffee can significantly boost alertness while driving.

Certain groups of people are more likely to drive drowsy than others, including younger drivers and shift workers, as you can see in the graphics below:

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In the slideshow below, you'll find more staggering statistics about driving drowsy, including the cost it takes not just on our wallets but our lives.

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  • 52

    The percent of drivers who have ever driven drowsy

  • 37

    The percent of drivers who have driven drowsy in the past month

  • 5

    The percent of the general population that has fallen asleep while driving in the last 30 days

  • 28

    The percent of commercial drivers that has fallen asleep while driving in the last 30 days

  • 168 million

    The number of people who have driven drowsy in the past year

  • 1 In 7

    The number of drivers ages 16 to 24 who have fallen asleep while driving at least once in the past year, compared to 1 in 10 of all drivers

  • 15

    The percent of heavy truck crashes that involve fatigue

  • 55

    The percent of fatigue-related crashes caused by drivers under 25 years old

  • $12.5 billion

    The yearly monetary losses due to fatigue-related crashes

  • 1,550

    The estimated number of deaths that occur each year due to fatigue-related crashes

  • 6

    Getting less than this number of hours of sleep <em>triples</em> your risk of getting in a sleep-related accident

  • 18

    The number of hours spent awake it takes to impair driving to the equivalent of being legally drunk. Both driving drunk and driving drowsy double your risk of causing a car accident, according to a 2012 study.

  • Every 100 Miles Or 2 Hours

    How often drivers should schedule a break during long trips

  • 14

    The number of states (and Washington, D.C.) that provide police training about drowsy driving