Driving tired is as bad as driving drunk

20 January 2011

Driving while tired can have the same effect as being over the legal blood-alcohol limit, say Dutch researchers.

The study, as reported in the Telegraph, was conducted by researchers at Utrecht University in the Netherlands.

It showed that after just two hours behind the wheel, drivers made the same mistakes they would if they had 0.05% blood alcohol content, which is more than half the UK legal drink drive limit.

After three hours driving, their performance corresponded to 0.08% blood alcohol content – the national limit. By four-and-a-half hours, it was equivalent to 0.10%.

Driver tiredness is a thought to be responsible for 20% of road deaths in the UK.

The researchers said, "Our data show that drivers should take sleepiness behind the wheel seriously. It is one of the primary causes of accidents on motorways.

"Yet drivers themselves are sometimes unaware of sleepiness, reduced alertness and corresponding impaired driving.”

To stave off sleepiness:

1. Have a goodnight’s sleep before setting out on a long journey.
2.  Plan journeys to include a 15 minute break every two hours of driving – and make sure you take them.
3. Share the driving if possible.
4. Avoid making long trips between midnight and 6am, and 2 to 4pm when natural alertness is low.
5. If yawning begins, stop in a safe place as soon as possible (not the hard shoulder of a motorway). Proper sleep is needed but a good counter measure is to drink two cups of strong coffee or a high caffeine drink and nap for 20 minutes.

It is important to note, caffeine takes about 20 minutes to take effect and this countermeasure should only allow you to continue driving for a short time.

The benefits of the break will wear off quickly. Trying to repeat them will not have the same effect, and the sleepiness will return.

There is no evidence that playing loud music or opening the windows help keep drivers awake.