Or almost. The truth is that this rule is 97.5 per cent of drivers. For the remaining 2.5 percent, or one in 40, the mobile phone has no negative effect on driving performance. These whizzes with telephone line are called superconductors, and thwart all the predictions of cognitive models of attention while driving.

At the University of Utah, Jason Watson and David Strayer placed volunteers in a driving simulator and measured their reaction times and braking distances with or without a telephone conversation. They then noticed that very few drivers fared as well with a phone than without. Normally, we consider that the brain can only focus on one task at a time, because the conscious processing of information involves an area called the prefrontal cortex, which is a bottleneck of external stimuli. Superconductors are a challenge to psychologists, who now want to further their studies with fighter pilots, among whom we should find more people able both to take instructions via radio and carry out complex operations. Beware, however: the superconductors are rare, and you have the same chance to be part of that fire five times in a row “pile” to a game of heads or tails.
Source:pourlascience