these are popping up in the DFW suburbs where they can be built from scratch. The standard setup is retail at street level with apartments on top and parking underground or at least concentrated in one large garage. They're not completely car free in the center of the development but it doesn't make sense to drive on the interior, there's no point. I think the streets on the inside are there mostly for fire/emergency access. It's ok I guess, the developments are like walking around an amusement park but it's retail instead of games and rides.
Another setup I see in the exurbs are planned communities. You basically take everything a neighborhood needs and build a wall around it. My sister lives in one on a lake, it's pretty neat, everyone drives golf-carts around instead of cars which is funny/interesting. Also, they have their own holiday festivals and events so the community is pretty close knit. My sister's kids know all the other neighborhood kids and all the parents know each other. The parents keep an eye out and so the kids are given a lot of freedom to roam and do kid stuff they wouldn't normally be able to do in the standard suburban neighborhood with heavy and fast traffic everywhere.
You can have largely pedestrianized areas in the interior with these sorts of things but, in general, you need to provide parking because a lot of people are going to need/want to use a car to get to them even if they're on some sort of transit route.
They also tend to work better in moderate climates. One example of something along these lines in the Bay Area is Santana Row. Very clearly artificial but still relatively pleasant.
Another setup I see in the exurbs are planned communities. You basically take everything a neighborhood needs and build a wall around it. My sister lives in one on a lake, it's pretty neat, everyone drives golf-carts around instead of cars which is funny/interesting. Also, they have their own holiday festivals and events so the community is pretty close knit. My sister's kids know all the other neighborhood kids and all the parents know each other. The parents keep an eye out and so the kids are given a lot of freedom to roam and do kid stuff they wouldn't normally be able to do in the standard suburban neighborhood with heavy and fast traffic everywhere.