It's been around for years; it's called "policemen".
A policeman can't tell if someone looking at the road is in fact daydreaming and mentally miles away.
And no-one thinks sheer speed alone kills – so there's no point constructing an argument to disprove that. We're not that bloody stupid.
I maintain that going slower reduces the chance of an accident, because everyone has more time to react. If I glance that the stereo for a second, I've travelled less distance; if I fade to the other side of the road, an oncoming driver has more time to avoid me and more time to stop – etc etc etc.
You really think that if we all zipped aroudn town at 50mph we'd be just as safe?