@CatherineFlick also think about how, as cars and trucks get more quiet, the sound of a city will change. We've grown up learning that the natural sound of a busy city is...mostly related to the sound of internal combustion vehicles. Think about what our children's generation will unconsciously think of as the sound of a city -- more "eeeee" sounds from electric vehicles, and also perhaps...more sounds of nature and of people!
(There's a rather gross-er example of this: as bars and taverns started to ban indoor smoking, the smell of cigarette smoke in those places went away, and we learned that, in some sense, the "natural smell" of a bar or tavern was...that of urinal cakes! Which I guess is better than the smell of cigarette smoke...)