In addition, a 2012 white paper by the National Safety Council – which includes references from more than 30 research studies – found that “the cognitive distraction from paying attention to conversation – from listening and responding to a disembodied voice – contributes to numerous driving impairments” including inattention blindness (when drivers look at, but do not “see” objects in their path), slower reaction times and problems staying in a lane. That paper concludes: “Driving while talking on cell phones – handheld and hands-free – increases risk of injury and property damage crashes fourfold.”
I would rather be surrounded by drivers with four or five beers in them than drivers who aren’t even trying to pay attention.