Could be both, too. I'd also be interested in seeing the correlation between the political power that poor and/or non-white communities have in the area, and t

Could be both, too. I'd also be interested in seeing the correlation between the political power that poor and/or non-white communities have in the area, and the likelihood that they get stuck with such things in their neighborhoods. Anecdotally I've heard stories from the days of widespread highway construction, when both rich, white and poor, black neighborhoods were supposed to get highways built right through their neighborhoods, but only the former managed to lobby successfully against them.