You don't know my reaction times and you are blaming a piece of equipment for human incapability. Some people can drive while talking on multiple radios, and some people can't. The problem is that (in the US) we do not have graduated licenses, like they do in Europe. In Germany, if one does not pbutt the Autobahn portion, one may not drive on the Autobahn. And yes I lived there for seven years, drove an E-Type Jaguar, and returned from my marriage in Basel driving an average of 130mph from Munich to Frankfurt. This was not unusual. I also drove an XK-140 Jaguar at Laguna Seca (amateur) and while there were no radios at that time, Michael Schumacher now drives a Ferrari in Formula One and talks on the radio at the same time.
On should not blame cell phone technology for human failure. Some people can actually talk and drive at the same time. Some people can't. Most police talk and drive at the same time. If a person can not drive and talk at the same time, maybe their license should have that restriction, like eyeglbuttes.
By the way I always pull over to talk on my cellphone, even though it's got a microphone and speaker, but I am now 67 years old and recognize my limitations. My wife said that I could look for my retirement Ferrari (an old one - like me) and I know that I will never drive it faster than the posted speed limit. But talk on the radio while driving? Piece of cake. Only one radio?
As far as text-messaging, it is simple to memorize a keyboard. I have a dash-mounted laptop computer and can select keys while never taking my eyes off the road - although I rarely do this - because the display is mostly automated. As an aside, my third son, just out of being a teen-ager, text-messages, with the phone held at his side. He never has to look at it.
Anyway, this is too much time to spend on this subject, so I leave. One thinks what one thinks. I'm beginning to think that if one says one cannot drive and talk on the radio it is that person that has a problem, and is projecting their problem onto others, who do not have that problem.