The study from VTI (Swedish National Road and Transport Research Institute) shows that the attention of drivers is negatively influenced by a telephone conversation, whether it is with a handsfree or hand-held mobile phone. The participants were however a lot more positive about using a handsfree than a hand-held phone while driving. They also had the impression that their driving performance was better when using a handsfree than a hand-held phone. This was in spite of the fact that the study does not show any differences in driving performance between handsfree and hand-held mobile phones.
From the standpoint of traffic safety, it was found that it is more unsafe to ring up with a mobile phone than to talk with a mobile phone. Drivers attempted to compensate for handling the mobile phone by slowing down, but found it difficult to drive without deviating from a straight course.
Two smaller experiments, involving reading SMS while driving and looking at a DVD film while driving, were also carried out. These two experiments ought to be extended so that more reliable conclusions may be drawn from them.
The results of this study were previously reported in conjunction with the Tylösand Seminar in 2003 and the Transport Forum in 2004.