A quarter of UK motorists have admitted to driving while tired in the last six months, according to a survey.
Of these, 42% opted to carry on behind the wheel rather than take a break, the survey of 2,000 adults by insurance company esure found.
Carrying on while fatigued was worst among 18-34-year-old drivers, while Londoners were the ones most likely to continue when tired.
The next-worst region for fatigued motorists not taking a break was the East Midlands, followed by south east England, north west England, and Yorkshire and Humberside.
Men (48%) were more likely than women (32%) to stay at the wheel when tired.
Andrew Lowe, head of motor at esure, said: "The research presented alarming findings in the number of
motorists that ignore the danger of fatigue while driving.
"This is a particular concern at this time of year for people driving longer distances or unsociable hours to holiday destinations or the airport."