Silicon.com has news of an Australian report that regardless of handsfree you are more likely to have a car crash.
Looking in more detail you see the study was 456 drivers in Perth who were hospitalised! Might be a self selecting survey.
I have to say that handsfree is better than holding the phone even in the snailpaced London traffic. But what is also more important is the network operators have to discover a way of limiting text use in the car!