Caio at pexels
Source: Caio at pexels

Ever driven while asleep?  No?  Are you sure?

In America people fall asleep at the wheel all the time.  Many sleep experiences are microsleeps, brief “lapses of attention” where much of your brain is asleep – but not necessarily all of it.  Microsleeps are generally just seconds long.  On the highway, a three second highway microsleep means about 200 feet where you were out, unaware of what you did. So just how many car lengths behind the forward vehicle do you drive?  And what happens if they slow down for a text message, or to sip a coke so they can stay awake at the wheel?

But you don’t have to fall asleep to make driving errors. Even if technically awake, sleepiness slows our reaction times.  And because lapses of attention occur erratically, many of us don’t notice.  Until there is no choice.

Recognizing You're Asleep

Not that long ago sleep researchers in Dallas decided to check how well people characterized their sleep.  They put people to sleep for 10 minutes.

It was light sleep, mainly.  But by EEG criteria, plus the videocams of snoring, knocked out individuals, it was darn clear those people were asleep.

Yet 50% believed they had been awake the whole time.

They were shown the videotapes of themselves – demonstrating they were snoring, snorting, or plainly slumbering.  No, they told the researchers.  You made a mistake.  I was awake.  All that time. 

Now imagine the same situation in a car.  You begin to understand why traffic researchers are very excited about autonomous, self driving vehicles.

One in a hundred ten Americans dies driving.  Of those fatalities, according to Dr. Mark Rosekind, most recent director of the National Highway and Traffic Safety Administration,  94% are due to human error.

Trafficking in Sleep Loss

The American Automobile Association is very interested in car crashes.  It has a research division which works to prevent them.

One large study the AAA  recently performed looked at “minor” sleep loss – one or two hours less sleep than most people generally receive.  Lots of people have such nights.  Sometimes it’s due to alcohol.  Sometimes it’s shift work.  Sometimes it’s “social jet lag,” where people go to bed late on Friday and Saturday nights and try to readjust Sunday night – one reason Monday morning is the peak time of death in the U.S.  Others just stay up late some nights, to see a boyfriend or girlfriend, visit family, or just watch the end of the NBA playoffs.

In the AAA study, the odds ratio of a crash was 11.5 times higher if people slept two hours less one night than compared with other nights.  It was every bit as bad as driving with alcohol blood levels  at the legal limit.

Plus the accident number was an underestimate.  The study did not look at crashes between midnight and 6 AM, where sleep loss takes its worst toll.

People need sleep.  Every night.  Even if it’s hard to get.

Recognizing Sleepiness

For a lot of people, knowing they are undergoing microsleeps is difficult.  It’s even difficult for outsiders.  A study by Torbjorn Akerstedt of Swedish train conductors showed lots of them falling asleep on their night shifts with their eyes wide open.

They were standing.  They looked awake.  Yet their brainwaves told the researchers they were asleep.

What are some signs of sleepiness?  Recent research notes an old culprit – closing of eyes.  If your eyes are involuntarily closing on you,  you’re at much higher risk of a crash.  Similarly, blurry vision due to sleepiness also markedly increases your risk of crashing.


All over the world, when people feel sleepy at the wheel, they behave consistently: they open the window.  Turn up the radio. 

Sadly, these procedures work only for short periods, and overall not very well.

Others use caffeine.  Caffeine can be effective. Unfortunately, it is not always as effective as people think.  It can also wreck sleep the next night, or if you’re a shift worker, sleep the next day. The problem can become cumulative.

However, small doses of caffeine may go a long way.  Medical interns doing 24 hour shifts did better sipping an ounce of coffee an hour.  Others use green tea.  Both food drugs possess multiple other health advantages.

However, what appears to be the best countermeasure is to get sleep.  Interestingly, professional drivers, like truckers, appear to be relatively good at estimating when they are too sleepy to drive.  National standards limiting their driving helps a lot, too.

Bottom Line

Sleep is like food.  What do people do when they feel they’re starving?  If food is available, they eat.

Generally, the best way to deal with sleepiness is to sleep.  If you feel your eyes closing, or you can’t see quite as well into the distance, it may be a very good idea to get off the road and take a nap.

It may be hard to recognize microsleeps.  But people can train themselves to recognize their alertness.  These days cellphones are often blamed for crashes.  They should be.  Texting while driving is unsafe.

Yet when people use their cellphones in the middle of the night they may not recognize the risks they’re creating. Sleep loss makes us sleepy.  Microsleeps are very short.  Death lasts a very long time.

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