Well, let's get back to first priniples. You need to be able to transport goods, that is, put them on wheels. Beyond a certain mass, you also need some kind of drive train to move it. Muscles can't produce enough force. And you need the flexibility to reach any address. These are fundamental preconditions without which large cities cannot exist. You need all of this for construction, maintainance and providing basic supplies for people living there and removing their waste. These requirements lead to a system of streets and cars/trucks of some sort.

Modern society uses the same system for individual transportation, which makes it inefficient in densely populated areas. Banning individual car traffic works in cities works because alternatives can be more efficient and they are practical because of the short distances involved.