Direct Line, England’s leading insurer who commissioned a study at the Transport Research Laboratory, is hoping their findings will lend support to a total ban on the use of hand-held mobile phones while driving. The Direct Line study, carried out over three months, involved testing the reaction times and driving performance of a panel of volunteers using a sophisticated driving simulator. Researchers tested how driving was impaired by talking on a hand-held mobile phone, a hands-free phone, and when drivers had consumed enough alcohol to be above the legal drink-drive limit.

The results demonstrate that drivers' reaction times were, on average, 30% slower when talking on a hand-held mobile phone compared to being drunk and nearly 50% slower than normal driving conditions. According to the tests, drivers talking on a hand-held were less able to maintain a constant speed and found it more difficult to keep a safe distance from the car in front.

On average, it took hand-held mobile phone users half a second longer to react than normal and a third of a second longer to react compared to when they were drunk. At 70 mph, this half-second difference is equivalent to traveling an additional 46 feet before reacting to a hazard on the road.

Using a hands-free mobile phone also proved to be a considerable distraction for drivers. In fact, participants in the study stated that they found it easier to drive drunk than to drive and use a mobile phone (hand-held or hands-free). In addition, drivers using either a hands-free or a hand-held mobile phone significantly missed more road warning signs than when drunk.