Researchers also found that motorists take their eyes off the road to nearly a quarter if they use a satnav.
Revolutionary eye-tracking technology shows that drivers take their eyes off the road every nine seconds on average attracted by passing clouds, adverts, scenery and a host of other distractions, the 'Daily Mail' reported.
Researchers took 100 drivers and recorded where their eyes were focused during a 22-minute drive through a city, with the help of specialist glasses which pinpointed the exact focus of the eye by tracking microscopic movements in the cornea.
The experiment was captured on film and enabled to establish exactly where drivers focus their vision.
The study found that, on average, drivers spend 18 per cent of their time behind the wheel not watching the road. Those who use satnav devices spend 22 per cent of their time focused away from the road.
They spend 12 per cent of their time behind the wheel looking at their satnavs and 10 per cent on other distractions.
Average motorists spend 7 per cent of their time behind the wheel looking at buildings, clouds and scenery, 0.8 per cent of it gazing at adverts, 0.7 per cent reading maps, 0.2 per cent checking the radio and 0.1 per cent looking at their passengers, according to the study.
Only 2 per cent of their time is spent looking at oncoming vehicles and 0.6 per cent observing road signs.
Motorists spend 3 per cent watching pedestrians who are not crossing the road and checking their mirrors, the report said.
A separate study found that three-quarters of motorists admit being distracted behind the wheel.
The main distractions include fiddling with the radio or CD changer (54 per cent), drinking a beverage or eating a snack (47 per cent for each), making a call or texting on a hand-held phone (16 per cent for each) and dozing (4 per cent).