Yeah sure that sounds great, alert the human, but guess what?

The human is asleep, reading, writing, or drunk.... as has been promised elsewhere as one of the main advantages to a self-driving car.

"This future is better than the current one b/c you don't have to pay attention"

So if you're telling me I still have to suddenly pay attention, poof! up in smoke goes the advantage of this supposedly self-driving car. I can't take a nap, b/c I might have to wake up and grab the wheel when a ladder starts flying off the back of a truck towards me.

This is not a consistent picture. It's just a bunch of fairy tales. Each day dream breaks down when it relies on a neighboring, magical scenario.

You're responding to one person's suggestion as though it presents the ultimate plan of those dedicated to this technology.