Tired drivers as bad as drunk drivers

(PhysOrg.com) -- New research shows that driving for only three hours at night has a similar effect to driving under the influence of alcohol, and even two hours can be equivalent to a couple of drinks.

Researchers at Utrecht University in the Netherlands decided to find out how being tired affects driving ability. They recruited 14 subjects, all healthy males aged 21 to 25, and asked them to drive at night, under supervision, for two, four and eight hour stretches. The driving periods were 3 am to 5 am, 1 am to 5 am, and 9 pm to 5 am.

The volunteers drove along a at a constant speed of 130 km/h (80 mph) and were required to remain in the center of their traffic lane at all times. Driving safety was monitored using video recordings, and the deviations from the center of the lane was measured.

The researchers, led by Dr. Joris C. Verster, compared the results to the known effects of alcohol on driving and found that two hours of driving produced the same errors as 0.05 percent (over half the UK drink driving limit of 0.08 percent). After three hours driver performance was equivalent to 0.08 percent, and after four and a half hours it matched the performance of a driver with a blood level of 0.10 percent of alcohol.

The report, published in the Journal of Research, concluded that should take seriously as it is one of the major causes of accidents on motorways. Drivers may be unaware of their own reduced level of and their tiredness. The researchers also said playing loud music or opening windows had little effect.

The paper concluded that continuous driving time at night should not exceed two hours, and recommended governments impose a maximum two-hour limit at night to try to reduce the number of accidents and fatalities caused by tiredness while driving. They acknowledge that this may be difficult to police as there is no accurate way of measuring the extent of a driver’s tiredness.

According to the researchers up to 20 percent of traffic accidents in industrialized countries can be attributed to sleepiness while because of long periods behind the wheel, or because of the use of medicinal drugs.

Explore further

Night-time driving over long periods increases risk of accidents

More information: Prolonged nocturnal driving can be as dangerous as severe alcohol-impaired driving, Journal of Sleep Research, DOI:10.1111/j.1365-2869.2010.00901.x

© 2010 PhysOrg.com

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User comments

Jan 21, 2011
This doesn't seem like a very fair test. I assume a simulator was used? And only 14 subjects?
Also driving for 2 hours at 9pm on a busy motorway would be very different to driving for 2 hours at 3am on an empty one.

The Mythbusters did a nice test of this though, and found being very tired (ie awake for >24 hours) is waaay worse than being just below the legal drink drive limit.

Jan 21, 2011
When, and how much, did these guys sleep relative to the driving times? Were they up all day before they did these tests?

Jan 21, 2011
Unfortunately there is no cure for the biggest group of bad drivers...the stupid ones.

I wholeheartedly agree. "Prepare to Merge" does not mean stop and put your blinker on...idiots.

Jan 21, 2011
In terms of what? Reaction times? Situational awareness? Judgment?

These morons are acting like "deviations from the center lane" is the only factor to good or bad driving...

Jan 21, 2011
We don't need limits on night driving hours. We need rest stops every few miles so drowsy drivers can pull over. I've driven cross country quite a few times and there is nothing worse than being drowsy and not having a place to pull over. You can't just exit because there is usually no place to pull over if you exit without the cops bothering you, especially if you have out of state plates. And it wasn't always at night. You get drowsy during the day too.

Jan 21, 2011
You can't just exit because there is usually no place to pull over if you exit without the cops bothering you, especially if you have out of state plates.

I know right? We know you're tired as hell and will most likely kill someone or yourself if we make you get back on the road...but do it all the same. Because our cop brains can't simultaneously handle the concepts of "spirit of the law" and "letter of the law" without either exploding or spontaneously combusting...

Jan 21, 2011
We live in a society where we have to work for a living. This means that we have to work to survive; anywhere between 8 and 16 hours in a day. On average a person would drive or commute to work for 30-90min, work for 8-12hrs, and finally drive or commute home for 30-90min. For most of us it is not a choice and I don't care who it is, but even after 9 hours being awake and doing nothing a person will get tired. So saying that we shouldn't drive when we are tired is kind of hypocritical; you can't have it both ways, be productive and be well rested. Instead of limits on motorists this may entail to be enacted, I am pro for people being responsible for their own actions, so if you drink too much or work too much and kill someone, it is your fault alone; no need to sue or blame anyone for own stupidity, no need to waste anyone's time for research to get a pretty obvious answer, and no need to provide our law machine with more ways to squeeze the motorists.

Jan 21, 2011
We should start a number of new groups and programs:

--Mothers Against Tired Drivers
--add EEG's to traffic stops (preventing DWS, driving while sleepy)
--Charge employers with criminal negligence if they serve their employees enough work to make them tired when they drive home.
--Fine people for public narcolepsy
--"Friends don't let friends drive dreaming"

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