Do You Drive Tired?

The real risk behind the wheel

December 2, 2011

A recent study from Australia has uncovered a road hazard that's as potent as alcohol: too little sleep and a long workday.

Researchers gave driving-performance tests to 39 people after they had stayed awake for 17 to 20 hours, and again after they had quaffed enough alcohol to raise their blood alcohol levels to 0.1 percent, which is the legal level of intoxication in much of the US. (The tests included checks of perception and reaction time.) Half of the participants performed as poorly when sleep deprived as they had when drunk.


"People know it's dangerous to drive drunk, but not that driving home after a marathon workday could put you at risk for an automobile accident," says lead study author Ann Williamson, PhD, executive director of the Injury Risk Management Research Centre at the University of New South Wales in Sydney.

Reduce the risk by getting some sleep; but if that's impossible...

Gauge your sleepiness. You may be overtired if you could easily fall asleep sitting in a meeting or quietly reading in your office, or if you feel excessively sleepy after lunch. You are sleep deprived and should not drive if you've dozed during a conversation or at a red light.

Try a short-term solution. Sleep deprived? Get someone else to drive, or find a place to sleep for the night. Caffeine can restore alertness, but only temporarily—half an hour or less. Don't count on loud music or cold air from an open window or air conditioner to do the trick, adds Williamson.

Aim for more sleep. The long-term solution? Balance work and rest, making sure you sleep after being awake for 17 hours, advises Williamson.