I think it's very common to see that type of behavior whenever the demographics will support it. The races tend to self-segregate, despite society's best effort

I think it's very common to see that type of behavior whenever the demographics will support it. The races tend to self-segregate, despite society's best efforts to stop it. It's really the bigger cities that are exceptions in this regard, because their demographics and geography are generally such that you can't escape the diversity. Anywhere that doesn't have those hard geographic and demographic constraints self-segregates naturally.