A poll of 2,000 motorists found a whopping 86% have been in control of a vehicle while tired at some point. Some admitted they have driven while 'dangerously tired' - and have even nodded off.
Almost 8% have had a near-crash due to getting behind the wheel when exhausted and 41% admit they've powered on to their destination despite feeling exhausted.
The research was commissioned by insurance firm Allianz, which also conducted a scientific study which found motorists are twice as likely to drive unsafely when tired.
Weary drivers made double the number of mistakes on everyday driving skills than those who were well-rested, with reaction times, precision, control and overall awareness all deteriorating.
Two groups of drivers were tested on a variety of driving skills, including emergency braking, parallel parking and a real-world road course.
Caroline Johnson from Allianz said: "We want our roads to be as safe as possible for all motorists and our claims data and test results clearly demonstrate that driving tired puts your family, friends and road users at significant risk.
"With many students and their parents likely to be getting in the car and heading off to universities up and down the country, we want to highlight the risks and hope our experiment shows just how dangerous it can be.
"If you're planning an early morning or late drive, try to get some extra rest, as this can make a big difference and the risks are simply too great.
She added: "Road safety begins with responsible driving, and that means knowing when to rest and prioritise adequate sleep."
The most popular method to keep awake while driving is opening the window (60%), cranking up the volume of their music (30%), drinking a strong coffee (26%) or singing along to an album or song they know (23%).
Despite many admitting they do it themselves, 50% agreed people driving tired should be treated just as seriously as those driving under the influence of alcohol or drugs.
A further 79% believe it is more dangerous than speeding, according to the OnePoll.com figures.
Multi award-winning driving safety expert for some of the UK's leading car brands, Paul Ripley, added: "Driving when you're tired isn't just about feeling a little sluggish - it seriously affects your ability to react, make decisions, and control your vehicle safely.
"Our experiment shows a lack of sleep can make you a danger on the road."
