Earlier quoted context omitted.
A circle is harder to build and has more issues regarding sunlight. The sun hitting the building(s) is both a benefit (solar cells) and a problem (heat generation) at the same time. A linear structure will get a much more even energy distribution than a circle. Also one of the goals of the project is to reduce the energy needs of the population by making ways shorter. If you spread a city out on a circle, you got a m…
I think transport would be infinitely worse in a linear city. In a traditional street network, there are many ways to get from A to B and one link being unavailable is not the end of the world. Forcing everyone onto essentially the same street is guaranteed to cause both high fragility and high congestion, since everyone has to squeeze into the same line.
At the simplest there would be one line connecting from end to end, which should be the fastest and the one with the fewest stops. But then you have smaller lines, travelling in their own tubes, connecting local areas. That way you can travel between any two points relatively fast and avoid congestion. You can build redundancy into this system. But also, it's not a catastrophe on a normally 20 minute trip if there is blocked section and you have to walk a few minutes, take a local connection to bypass the blockage and then go on. Happens to me all the time...
The big benefit in a linear city is that the transport pods never need to turn around. You also don't need to manufacture curved rails or things like that. You can build structures like that in a "2D" city, but it's harder.