[fsloth]

I think you are presuming a method of implementation and routing with some location in mind where this would not be that applicable.

I disagree most strongly about the need to dig up and destroy walkways. We have 3 dimensions to work with - to go up, or, down. In any case I would see this analogous to a public urban rail system such as a metro or a tram.

I don't see it as a big issue to dig a tunnel for this - lots of cities implement rails and such that go wherever public transportation is needed.

The only argument which I agree is the biggest hurdle - which is actually an unknown - is how to make the system sufficiently robust so you don't need an army of engineers to maintain it. The fact that there are no known robust systems is not a good enough argument. Lots of mechanical systems were in the development over a century after someone figured out how to make them as practical to make a major impact(steam engines, automatic weapons).

How robust is the most robust implementation possible and how expensive it is are the two major questions to my mind. If it's too expensive to maintain - then it's too expensive to maintain.

[rebootthesystem]

The point you should be agreeing with is that regardless of how you build it --dig a tunnel, rip-up the sidewalk or go vertical-- the cost of such a system defies a comparison to a simple fleet of buses by a huge margin. I would venture to say one, if not two orders of magnitude.

I mean, the thing is ridiculous to such a degree that it is surprising to see anyone arguing in favor of it.

Buying a fleet of electric buses would make far more sense than this insanely ridiculous idea.