Worth noting regarding Barcelona is that this is, to a great extent, retrofitting a concept that already exists within the city to "new" parts. In Ciutat Vella,

Worth noting regarding Barcelona is that this is, to a great extent, retrofitting a concept that already exists within the city to "new" parts. In Ciutat Vella, there are a few "outer" thoroughfares, with the inner streets shared between cars and pedestrians. They are, however, narrow to the point where they are not really navigable by anything larger than a Smart Car moving at rolling speed, and it's very clear that cars are second-class citizens. Thus, this isn't really introducing a new "social order" as if this were to be done anywhere in the US.