1/5司机曾在开车时打瞌睡

Almost one in five drivers have dozed off behind the wheel, a shocking new report has revealed.

Of those who were nodding off, a worrying three in ten (29 per cent) have done so on the motorway doing speeds up to 70 miles per hour.

The report also found a quarter of men have fallen asleep while driving, making them almost twice as likely as women (13 per cent) to do so.

The Safety on Wheels Report, by Post Office Car Insurance, also looked at how often tiredness or a lack of concentration caused accidents.

Three in ten drivers have experienced an incident, from missing a pedestrian crossing to hitting another vehicle, because of a lapse in concentration.

Meanwhile, almost half (49 per cent) of UK drivers have driven while not concentrating.

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.'

Drivers are advised to take a 15 minute break from driving every two hours.

However, a third (36 per cent) are so eager to reach their destination they will ignore feelings of fatigue.

What’s more, almost one in five (18 per cent) will drive for longer than four hours without a break - while six per cent carry on for up to six hours.

But when tiredness strikes, drivers do resort to a range of energy boosting measures.

Just over a quarter (27 per cent) opt for a quick caffeine fix and buy a cup of coffee while 17 per cent pull over until they feel alert again.

Mr Havenhand added: '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.

'Drivers should ensure they plan ahead and rest before embarking on a long journey as well as taking regular breaks to recharge their batteries.

'In some circumstances, if they really do feel too tired to concentrate on the roads, they may want to consider an alternative method of transport.

'A momentary lapse in concentration might result in a scrape, or worse an accident, that could otherwise have been avoided.'