I’ve now seen multiple references over the past few months to research on this point. The latest is a study in the British Medical Journal that is summarized in an article in the NYT today. The message seems quite clear: it’s not about the diversion of focus from the car and road to the device, the distraction is the conversation:
“There just doesn’t seem to be any safety benefit by restricting drivers to hands-free phones,” said Rae Tyson, a spokesman for the National Highway Traffic Safety Administration. “It’s the cognitive overload that sometimes occurs when you’re engaging in a conversation that is the source of the distraction more so than the manipulation of the device.”
What’s perhaps most odd about this research is how unnecessary it is – any driver knows, intuitively, that this is true.