I often drive with the radio on, tuned to a public broadcaster, but find I can easily ignore the radio, whether music or voice. My participation in the task of listening does not necessarily require much attentional commitment, and one can divest easily, if need be. Of course, if the rate of information flow on the road ramps up (e.g., finding critical signage on a busy commuter highway in an unfamiliar city whilst going with the flow of high-speed traffic), then the radio goes off and all conversation in the car is verboten, simply because even that minimal level of attentional commitment to non-critical tasks is too much distraction in the circumstance.

The thing about cell-phones and conversations is that they are non-driving events that demand a certain level of attentional commitment. To respond to the conversation, I need to follow it, and to do that requires more of my attention than perhaps ought to be allocated in many driving circumstances. It is what the need for continuity does to the division of our attention that is the killer.

Personally, I take it as a given that folks who are prolific cell-phone users are somewhat committed to their conversations. If you can’t bear to turn the phone off, then chances are you will not readily turn your attention off should the phone ring. And that’s where your risk of traffic injury and fatality begins.

Not to place all the blame on cell-phones, though. Easy to imagine that moms driving with kids are also distracted by what is taking place in the back seat, and are unlikely to easily divest their attention from that other parallel task.

Anyway, these come from my good friend Tim:

a) How much time you spend driving i.e. the less exposure you have to this dangerous human activity, the less likely you are to become one of the statistics. Over the years highway fatalities (USA) have ranged approx. between 40 and 50 thousand per year yet the recent economic downturn and high fuel prices have reduced miles driven by Americans, thus fatalities have been reduced to approx. 37 thousand in the most recent period measured (the lowest since 1961).
b) When you drive i.e. statistics show the greatest number of accidents and fatalities occurring between midnight and 3:00 am on Saturday and Sunday mornings. So, without belaboring the obvious cause of this (the most problematic drug in our society; alcohol) the prescripion is straightforward; stay off the road on Friday and Saturday nights.
c) Driving is an inherently dangerous proposition for the human animal. Cognitive research as well as common sense supports this view. Over the millenium (evolutionary) selection pressures did not include e.g. driving a half ton metal cage at the speeds (e.g. 1-100mph) and conditions (car congestion, roads, weather, etc.) we experience. Perverse note: on the upside perhaps these selection pressures are now beginning to operate.