> including the widespread surveillance required to enforce certain proposed traffic restrictions

But 15-minutes cities aren't about traffic restrictions. I might be wrong but this seems like people are conflating low traffic zones (which can involve the kind of automated system to limit traffic that you seem to refer to) with 15 minutes cities, which is an idea in urban planning to decentralize services (the "15 minutes" is intended as "you can reach anything you need every day with 15 minutes of walk", not "you won't be allowed to travel more than 15 minutes")