In the United States, *everything* can be used as a system of reinforcing existing class and race difference, from public schools to private housing and anything in between. Which is pretty consistent with the "uses and gratifications" or "garbage can" approach to social institutions, arguing that institutions are used according to specific interests and agendas of individuals involved in them rather than by their intended or official missions.
If you want to change that, you need to address the class structure of the US society instead of barking on popular distractions, like "gentrification" or public transportation.
Besides, everyone in my neighborhood (empowerment zone in downtown Baltimore) loves gentrification. It brings people with income and businesses - meaning tax base - to the ailing cities, thus contributing to urban renewal and limiting suburban sprawl..
Wojtek