A few thoughts on this matter: 1. Roundabouts are safer and better with human drivers but bad from a usability standpoint. It's annoying to drive, slower, and

A few thoughts on this matter: 1. Roundabouts are safer and better with human drivers but bad from a usability standpoint. It's annoying to drive, slower, and makes people feel nauseous when driving through many. When we have road usage of autonomous vehicles surpassing 50%, I suggest to remove them. 2. Two-Leveled intersections without left turns seem cost effective and highly advantageous in cities. To lower the cost even further, it may be possible to design them for vehicles only (much lower ceilings needed, so much lower cost). Left turns can be achieved (especially in the US this is viable) bu going right three times (going around the block). Two-leveled intersections without left turns can reach 100% capacity in all lanes from all directions. 3. Lane-specific traffic light already may increase efficiency on intersections. Imagine a 2x2 intersection from both directions: the right turns can be green (where cars turn right on the rightmost lane) while through-traffic can use the left lane.