Using a hands-free mobile phone in a car while driving poses no less danger than a handheld one, because the hazard does not relate to your hands, but with your brain.

New research suggests that regardless of the device used, all telephone conversations while driving are dangerous, as they affect attention and visual processing skills significantly.

Many have previously believed that hands-free kits are safer to use in a vehicle as both hands remain on the steering wheel.

But David Strayer, from the University of Utah, who led the research, told The New Tork Times: “It’s not that your hands aren’t on the wheel. It’s that your mind is not on the road.”

The findings of the research, published in the December issue of The Journal of Experimental Psychology: Applied, has led to a call from the National Safety Council — a US pressure group that has campaigned for drunk-driving awareness and the enforcement of seat-belt laws — for an all-out ban on the use of phone calls while driving.

In America a dozen states and several cities and counties enforce bans on using hand-held mobiles while driving, but not when using hands-free devices. Similarly, in Britain, using a mobile phone while driving was banned in 2003, but it is not illegal to use a hands-free kit while driving.

Earlier experiments and road-side surveys have indicated that drivers talking on a mobile phone are four-times more likely to be involved in an accident.

The new studies have revealed several factors to explain why phone conversations have such a drastic effect on a drivers attention. They suggest that talking on a phone generates mental images that conflict with spatial processing required for safe driving.

Experiments that track eye-movements show that while most drivers keeping looking side-to-side, during a phone conversation they stare straight ahead.

The American research found that the overall result of talking on the phone while driving is that the brain processes less of the information passed from the eyes, leading to drastically slower reaction times.

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