Deliberately? I know that, when the highway boom was getting started, these things tended to be built through the poorest neighborhoods since the property was cheaper there, instead of planning what would be best in the long run.
My impression is that the canal and levee system in Louisiana tend to follow the natural terrain, more or less.
My wife was there when the Chicago expressway system was built. The Expressway was built along existing racial boundaries. You can't see this anymore, because most of the white people have moved to the suburbs.
I find this interesting, because I live in northeast Florida, and growing up we had black neighborhoods and white neighborhood intermingled like checkerboards. Now the divisions are invisible because all those old neighborhoods are integrated. The rich have their gated communities, but the middle and lower classes didn't split apart.