On the road: Sleep deprivation as risky as alcohol

Chance of a crash goes up 15-fold when driving on less than four hours' kip

Drivers who hit the road on less than four hours of sleep are at least as likely to be involved in a crash as drivers who have too much to drink, a US study suggests.

Brian Tefft, senior researcher at the AAA Foundation for Traffic Safety in Washington, DC, reviewed data on more than 6800 road accidents between 2005 and 2007 to study the effects of sleep deprivation on driving.

As part of an earlier study, the drivers in these accidents were interviewed in depth by investigators from the US Department of Transportation.

Mr Tefft classified the drivers into those who were "culpable" for a crash and those who weren't.

Drivers whose errors, actions or lack of actions led to a crash were deemed culpable, whereas those involved in crashes caused by external factors, such as brake failure or poor infrastructure, were not.

His findings showed that people who drove after getting less