> I basically agree that cities of a certain density are too dense for cars, but SF isn't really there.

Depends on where you live. If you live in the outer areas (south of bernal heights, outer sunset, etc) you might need a car but most other places you can get around easily with transit, walking, or biking

There is a difference between needing a car (i.e. I cannot live without it) and public transport being so good that you do not want one and the density being too great to support cars.

My experience living in the Lower Haight a few years back was that buses were slow, infrequent and required multiple transfers unless I was going to a few select places. Cycling was ok, but man were there some big hills (potrero) involved, e.g. cycling back from the dogpatch was pretty tiring even for a young person in pretty great shape at the time. And taking a train from dogpatch to the haigh required going back through the city.

So I could definitely get by without a car, but it constrained where I would consider going pretty significantly.

On the other hand, driving was usually fine, but finding parking was impossible, which self-driving cars don't have a problem with. Of course, parking was constraining driving, so removing the need for parking would make congestion worse, but even pretty close to the city center I felt like driving was pretty easy, and if we structure our streets (and bus lanes) right, the demand for self-driving cars will be in the routes that do not have enough demand/congestion to sustain good bus service.