>>2805193
You can build perfectly straight transit lines in a circular settlement also.

Consult my crude drawing. You can have 4 perfectly straight transit lines and two ring routes that will put everyone very close to a station and the ability to get everywhere quickly with only 1 transfer. And top speed doesn't matter as much when your settlement only has a 6.58km diameter. Pare it with some of those moving sidewalks (like you see at the airport) and you have the perfect arcology with the perfect transit system and the ability to get anywhere quickly. It would also be more energy efficient.