A worryingly high proportion of male drivers have briefly fallen asleep at the wheel, according to a road safety charity.
Research by Brake reveals that 45% of men admit 'head-nodding' at some point, risking appalling crashes and endangering the lives of others.
If you 'head nod' - otherwise known as 'micro-sleeps' - you have already nodded off. These patterns of sleep can last from two to 30 seconds, meaning that a frighteningly large number of drivers have been temporarily out of control of their vehicles.
Overall, 31% of drivers confess to 'head-nodding' at the wheel while 7% reveal they have even fallen asleep completely.
Some 49%, meanwhile, have driven after less than five hours' sleep - nowhere near enough for safe driving.
Tired driving kills at least 300 people on UK roads each year, although the actual figure could be much higher as driver tiredness can be hard to prove as a cause of crashes.
Brake is therefore urging all drivers to help stamp out devastating crashes by making a pledge to always getting a good night's sleep before driving.
It recommends taking two-hourly breaks during a journey, as well as pulling over somewhere safe as soon as possible if feeling tired.
Copyright Press Association 2014