Studies from the National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety, show that drivers are four times more likely to have an accident if they are talking on the phone 'hands-free or not' while driving.

The reason, researchers say, is that drivers often become engrossed in their conversation, rather than focusing on driving, even if their hands are on the wheel. "Once a conversation begins, we don't see a difference between hand-held and hands-free," says Adrian Lund, President of the institute. The insurance industry is starting to put its thumb on the scales of which approach 'blocking calls or hands-free talking' is safer.

The Nationwide insurance company said last month that its customers who sign up for the call-blocking service from Aegis Mobility would be eligible for a discount of around five percent off their annual premium.