&gt;There are various reasons for this, part of those reasons is that, disproportionately, the poor tend to be relegated to mass transit.<p>I agree with that in most cases, especially in low density wealthy cities, where people would avoid using transit even if it were more convenient, just to avoid the general population.<p>But in the case of several Bay Area neighborhoods the opposite is true. All else equal, in the urban core people pay a premium to live near a major mass transit station.<p>I guess you need a critical mass of  upper middle class working people, good enough transit, and terrible traffic for this to happen.  I certainly never saw transit access marketed as a selling point before moving here from flyover country in the dot-com days.