By Will Roberts
Almost one in five drivers have nodded off while behind the wheel, according to a new report.
The figure was uncovered by The Safety on Wheels Report, by Post Office Car Insurance.
The study found that of those who had at some point fallen asleep while behind the wheel 29 per cent had done so on motorways at speeds of up to 70mph.
A quarter of men have fallen asleep while driving compared with 13 per cent of women.
'No measurement for tired driving'
Paul Havenhand, head of insurance at Post Office, said: "When fatigue strikes, drivers should steer clear of the roads.
"Anything that hinders their ability to concentrate is dangerous and could result in a potentially fatal accident.
"There is no measurement for tired driving unlike driving while under the influence of alcohol, yet it could result in an equally dangerous accident.
"Drivers who are so tired they fall asleep while on the roads pose a serious risk to themselves and other road users.
"Roads can be hazardous enough as it is, without drivers putting themselves or others at risk by setting out when their concentration has been impaired."
Take a break every two hours
According to The Safety on Wheels Report three out of 10 drivers admitted to a lapse of concentration causing an incident, be it missing a pedestrian crossing or hitting another vehicle.
Meanwhile, almost half (49 per cent) of UK drivers have driven while not concentrating.
Health and safety experts recommend taking a 15-minute break from driving every two hours, but over a third (36 per cent) admitted that they are often so keen to reach their destination that they try to ignore the feeling of tiredness.
Some 18 per cent will go without a break for longer than four hours while six per cent will be on the road for up to six hours without a break.
Mr Havenhand said: "Sometimes it can be tempting to forge on ahead with a planned journey but it should never override the priority people place upon their safety.
"A momentary lapse in concentration might result in a scrape, or worse an accident, that could otherwise have been avoided."