Earlier quoted context omitted.
A network of self-driving cars is a train, or could be considered one if engineered properly. Of course, self-driving cars don't run on fixed rails, which costs them a lot of popularity around here. People don't seem to understand that fixed rail is only good for transporting lots and lots of people, very efficiently and safely, from one place where they don't want to be to another place where they don't want to be.
Well, that depends on how you build your railways. The way I see it done in the US this is indeed the case, as the stations (especially in California) seem to be in bizarre places and there is rarely a way to get to say an airport by train. But you can also build railways that make sense. See Japan for an excellent example, as well as most of Europe. These get you from where you are to where you want to be quickly an…
Ideally the sprawl is minimized for maximum efficiency (in both enhanced inter-personal cooperation, living cost) but it's hard to sell that when gas is cheap, and land is plenty.
There's another issue unique to the US, is that there is a diverse spectrum of races, income levels, and cultural groups that make it hard for these different groups to live together in a dense area peacefully (as compared to a homogenous place like Japan). Much of the inane urban planning in The US is actually a result of people just trying to prevent black people or poor people from moving into their neighborhoods.