One in ten people who drive for work have admitted falling asleep at the wheel in the past year, according to new research.
The research also found that people who drive for work are more likely to drive after insufficient sleep.
Half of people who drive for work who were surveyed say they sometimes drive after less than five hours’ sleep, compared to just over a third (35%) of people who drive only outside work.
Road safety charity Brake and Green Flag, who carried out the study, said nodding off for just a second or two can kill.
Travelling at 60mph on a motorway (one of the main types of road where fatigue commonly occurs), a driver covers 27 metres (88 feet) per second, said Brake.
The chairity is now urging all companies with employees who drive for work to ensure they have robust systems in place to prevent tired driving.
Cathy Keeler, head of campaigns for Brake, said: 'Too many people are dying on our roads because people get behind the wheel when impaired through tiredness.
'It is outrageous that so many companies allow their employees to drive on company time when they are so tired that they actually fall asleep.
'It’s crucial that companies introduce thorough procedures to ensure employees are not endangering themselves and others when driving for work.’