I have a theory that large fleets of self-driving taxis will make congestion worse (compared to private cars). They have to drive to you, then drive wherever you want to go, turning one vehicle journey into two ( * ). There are lots of other factors to consider but that seems to be a fundamental problem with the taxi model. I'd be interested in replies that explain the flaw in this theory. I assume it is wrong because I haven't heard anyone else say it.

* It could be even worse. Imagine the morning rush - thousands of taxis have driven to peoples' homes and then driven them to their work/school. Then most will have to park until the next peak of demand in the evening. Either they park in the city, or they drive to an out-of-city parking lot, then drive back in to collect, then drive people home, then drive somewhere else to park until the morning rush. What would have been two vehicle journeys using a private car became six.