Sleepiness and driving is a dangerous combination. Most people are aware of the dangers of drinking and driving but don't realize that drowsy driving can be not only dangerous but fatal as well. Nationally, drowsy driving causes more than 100,000 crashes a year, resulting in 40,000 injuries and 1,550 deaths.

Sleepiness:

• slows reaction time
• decreases awareness
• impairs judgment
• increases the risk of crashing

While everyone is susceptible to drowsy-driving crashes, shift workers run a particularly high risk. Their natural sleep patterns are disrupted by working nights or long and irregular hours.

The human body is governed by an internal clock known as the circadian rhythm that makes a person want to sleep when it's dark and be awake when it's light. It causes periods of sleepiness between midnight and 6 a.m. -- the natural time for humans to sleep -- then again in the midafternoon.

But shift workers have to try to sleep when their body is telling them to be awake, and be awake when their body is telling them to sleep. As a person gets more tired, they begin to miss things they would normally respond to, resulting in careless and even dangerous errors, particularly when driving. The late night and early morning drive times are the most hazardous, with the majority of crashes occurring between the hours of midnight and 6 a.m.

Before hitting the road:

• Get some sleep:  most adults need 7 - 9 hours to maintain proper alertness.
• Schedule breaks:  about every 100 miles or two hours during long trips.
• Bring a buddy:  arrange for a travel companion to talk with and share the driving.
• Be alert:  avoid alcohol and medications that may cause drowsiness.

Prevent a fall-asleep crash while driving:

• Be aware of rumble strips. Drifting over rumble strips is a sure sign that a break from driving is needed.
• Find a safe place to stop for a break or for the night.
• Drink two cups of coffee, then take a short 15- to 20-minute nap. You'll get some sleep before the caffeine takes effect, and when it does, you'll wake up and be alert.

National Sleep Foundation

National Highway Traffic Safety Administration