Here's my observation: Even talking on the phone hands-free makes a huge difference to driving style. I have a friend who was an EMT and frequently drove Ambulances at high speeds no doubt while talking/distracted, and still today when I'm driving with him in a regular car, he often talks on the phone when driving. He is convinced that he isn't distracted, but I can totally tell, as the passenger, how different his driving is. Not staying centered in the lane, inconsistent speeds, slower reactions to other cars cutting him off, etc. and that's hands-free talking, not texting and looking at the phone. People call me all the time when I'm driving and even though I have Bluetooth, I tell them, I can't talk, I'm driving, I'll call you when I get home. People don't understand...
Now, that doesn't mean I never use my phone and drive. I frequently use my phone for navigation, but that's what a phone mount is for, it's no different than a GPS. I will admit that I may or may not text or read emails when in the drivers seat, but if I were to do that I would would always do it when stopped at a red light... I know that's not much better but if I'm driving, all I'm doing, is driving. Now, messing with the music/radio, I definitely need to work on that...