The study was based on Mobile Phone data from the United States. After isolating calls made solely from moving vehicles, they analysed the spike in phone use when cheap evening rates kicked in. they expected to see a rise in crashes, but were shocked to find none. From this they have concluded that the current belief, talking into a mobile phone while driving increases the risk of crashing by 400%, is wrong.

An explanation for this may be that when talking into a mobile phone drivers reduce their speed and up their concentration levels, as compensation for the perceived additional risk.

However, the study and the findings have been widely condemned with one critic pointing out that the rise in mobile phone use may have been due to passengers in the car and not the drivers.