This is the biggest problem with this. Since the computer can't know if the device is being used by the passenger or driver, government will eventually force the phone to be disabled at all times while the device is in motion to "save the children".
So no, I don't and will never support this no matter how many crazy idiots claim it improves safety. There are lots of ways to die, and the only way to stop them all is for the government to lock each person in a padded room with automatic light based on time of day, no electric outlets, TV turned to the government channel, and finally to push liquid nutrients under the door. You would sleep on the floor so you don't fall too far. And even with all of this, I'll bet some people will find a way to die.
Dying is a perfectly normal way for nature to get rid of idiots. We should let nature do its job.