Oh, god. On my motorcycle, nothing scares me on the road more than people driving cars. Not only are they not perfect, they are far from perfect.

This is true, but the fear that could prevent implementation is that you want that fear in your own hands, not the hands of something else. It's like trusting someone to catch you when you fall - statistically you know it's pretty likely, but there's something unsettling knowing you're relying on an extraneous factor, not YOU, to prevent harm.

But don't you also have to trust a bus-driver, airplane-pilot, etc. And all kind of things can go wrong with these human drivers: they might be drunk or under some medication, they can die in a sudden hart attack, they can just make bad decisions, or even worse - they can be commanded to land the plane into some tower.