"That's a bit harsh. All they really need to do is ban accidents."
Believe it or not, that's not quite as ludicrous as it sounds.
"Banning" something doesn't make anyone stop doing it, it just gives you legal recourse to penalise those who are *caught* doing it. The *intention* is to modify behaviour through the threat of being penalised. Nice in theory, but as many have said before, it only works on those who were honest to start with. The criminals, or the ones using their phones, or the ones running red lights are going to do it anyway.
So just "making" a law will change behaivour, but not in the way you want. In case of phone useage, it does not stop people from using their phones, it only means they better obscure the fact they're doing it.