Quick comment on Cecil’s answer to Is cell phone use in cars really dangerous?, I actually asked my sister (who works at the institute of transport economics, Norway) why it presumably was dangerous to use hands-free phones in cars. Most people, actually, are quite capable of having a conversation with passengers while driving a car. The problem with mobile phones it seems, is that persons not sitting in the car will talk to the driver in situations where he/she needs to be focused on the traffic. People in the car almost instinctively know not when to distract the driver (back seat drivers not included), and therefore will be less dangerous to conversate with.
ole