A large number of motorists are driving unsafe cars even in the treacherous road conditions caused by the cold snap, despite being aware that this could lead to a rise in car insurance premiums.
Many roads in the UK have iced up due to heavy snowfall and freezing temperatures over the past few days.
But research by webuyanycar.com found 22% of male motorists driving cars with poor brakes, and 21% taking to the road with bald tyres.
Of the 3,000 motorists surveyed, 14% of men use vehicles that do not have a valid MOT certificate, while 23% of women drive cars with chipped windscreens or broken lights.
In total, nearly three in 10 cars on the road can be described unsafe as they have one fault or another.
During wintry conditions, salt from the roads may pose a serious threat to drivers by impairing vision. But the study showed that many cars do not have sufficient windscreen wash.
While 16% of people drive in cars without a phone, 3% have broken seatbelts, the poll added.
Paul Coulter, of webuyanycar.com, said: "We all love a white Christmas, but cold conditions and long drives over the festive period make it especially important to keep your car in good working order. We'd urge people to get their cars checked before long drives.
"Being a responsible driver isn't simply about how you drive your car; it's as much about making sure that the vehicle you are going to drive is roadworthy. Our research indicates that 30% of cars on the road are a hazard to other road users and we're appealing to everyone to take their responsibility to other road users seriously."
© Press Association 2010