Comment by nojvek

If buses have dedicated panes where they don't have to interact with normal traffic they can easily hit 70mph. Australian highways in certain places have this system.

My favorite is Vancouver skytrain. While building highways they built a train track on pillars. It's fast and usually got me in and out of the city quicker than a car.

I imagine train tracks on pillars cost effective than underground tunnels. For a dense city it makes sense. Not for outskirts.