I feel like the problem involves a liability shift. If you stand or park on a railway track and get creamed, the pedestrian is going to be the target of blame.

I feel like the problem involves a liability shift. If you stand or park on a railway track and get creamed, the pedestrian is going to be the target of blame. We've come to the conclusion that the track belongs to the trains; at best the engineer can perform a limited, good-faith effort to stop and everyone knows that's not going to happen when you've got a kilometre-long, 10,000-tonne wad of physics rushing down slick metal rails at 60kph. But if you walk into the middle of I-5 at rush hour, we still throw the legal and financial liability at drivers. Everyone is supposed to expect a rando suddenly stepping into the road and brake/steer around them. That's hard for humans and potentially harder for machines. I could imagine a network of "autonomous only" roads which were much regulatorily much more like the rail infrastructure-- designed for minimum surprise (limited on/off ramps, limited turning points, predictable advance signing and marking, perhaps a block-control system to mitigate traffic flow) and limited recourse for pedestrians or human operators who enter the territory.