And the authors of the research found somebody speaking on a hands-free phone was 9% slower hitting the brakes and 24% more variable in their ability to keep a regular distance behind the car in front – the same level of competence as if they had drunk enough vodka to put them over the legal limit.
The research, conducted at the University of Utah, USA, used 40 volunteers in a driving simulator performing tasks in four scenarios: without distractions, with a hand-held phone, with a hands-free phone and while over the drink-drive limit.
Stuart Walker, head of corporate accounts at vehicle management company LeasePlan, said: ‘This study highlights the risks of using mobile phones when driving. If businesses want to protect themselves and their drivers they need a clear and well-communicated policy on phone use, whether handsfree kits are permitted or there’s a blanket ban on calls while driving.
‘We all know that sometimes taking a call on the move using a hands-free kit is unavoidable, but drivers must be aware of the impairment to their concentration.
‘If drivers are making calls, they would be better off stopping safely first.’