What would be an example city? Waymo just announced they're ramping up in Boston: https://waymo.com/blog/?modal=short-back-to-boston
"we’re excited to continue effectively adapting to Boston’s cobblestones, narrow alleyways, roundabouts and turnpikes."
Any small city in Italy is going to be 10X more challenging than Boston
Depends, which is harder: a narrow street or a three lane one with no obvious lane markers with people double parking?
the absolute chaos of Paris would also be challenging.
and the failure mode for some of them are steep drops off of cliffs
Various European cities come to mind: Narrow streets are something of a trope in certain movies/genres.
To be fair, many of those films do not portray human drivers in the best light.
Not grandparent but I was rather thinking of medieval city centers in Italy or Spain.
edit: Case in point:
https://maps.app.goo.gl/xxYQWHrzSMES8HPL8
This is an alley in Coimbra, Portugal. A couple years ago I stayed at a hotel in this very street and took a cab from the train station. The driver could have stopped in the praça below and told me to walk 15m up. Instead the guy went all the way up then curved through 5-10 alleys like that to drop me off right right in front of my place. At a significant speed as well. It was one of the craziest car rides I've ever experienced.
Do we really need FSD cars (any cars, actually) in medieval city centers?