> Atop those efficiencies, removing both the constraint of having a driver and the constraint of excessive safety systems to make up for human inattentiveness means AVs can get drastically smaller as vehicles, further improving road utilization (imagine lots of 1- and 2-seaters zipping by). And roads themselves can become narrower because there is less room for error with AVs instead of humans.
The first part is mostly describing taxis, so the incredible efficiencies relative to the status quo can be loosely observed through them. Just subtract out wage and a slight "technological scale" bonus, and you can estimate what it would be. Then add in the expected investor returns for being a technology company and see the improvements disappear.
The second part, I wonder. Cars already average under 2 occupants, with most just being the driver. If this is what is was needed for significantly smaller cars, we would already have them. Lack of smaller cars is mostly a cultural issue, not a technical one.