> it's not reasonable to expect the following driver to constantly be considering the possibility that the driver in front will slam on the brakes for no reason
Whether or not it's reasonable is immaterial. If you constantly consider the possibility of the cars around you to do something unexpected, then you're more likely to avoid death and destruction. As well as prevent the death and destruction of the people around you. It's called defensive driving.
Maybe it's unfair, or too much to ask, or just too difficult. But it's reality.
I'm rooting for self driving cars because I believe that, theoretically, they'll do a much better job than people. In the long run.
However, today, you have to pay attention or you might die. And even if you pay attention you still might die.
My dad told me a story about a coworker he had who was in a car accident. He was sitting at a long line in the highway at a tollbooth. It was foggy. My dad's coworker was watching the fog behind him like a hawk because he didn't feel safe just sitting completely stopped in the highway. A semi-truck appeared out of the fog moving at high speed. My dad's coworker cranked his steering wheel and tried to accelerate off to the side of the road but got rear ended by the truck. He was lucky. Because he was already headed away, this car got bumped out into a field. His car was destroyed and he got a bunch of injuries, but he lived. The people in front of him in the line were not lucky. A bunch of them died.
It's not fair or reasonable. But being constantly considering possibilities saved this guy's life. The other people are dead.