I voted don't know. Don't many cities already forbid vehicles in historic districts simply because they weren't designed for motor vehicles?

If not, that would be reasonable, but it wouldn't be appropriate to ban vehicles simply because it is crowded. It could hurt business and possibly discourage tourism. Cars (and we have much larger cars than Europe), people, and bikes all work well cities in the U.S. such as New York and Washington D.C., so it can work, but there just have to be accepted rules for people to follow.