Using phone handset whilst driving

So whats the difference between a hands free and using a handset? You're still having a conversation down the phone. Ok, so you've got an extra hand to use but think of all those disabled people with only one arm who still drive.

Don't forget that they have special device fitted in their cars, like a ball shaped joystick on their steering wheel to enable them to turn the wheel 360 degree.

it's much more complex than you think.