A great post on the always excellent Sociological Images blog talks about what leads people to different transportation choices as part of their lifestyle.  Car use tracks with how young your neighborhood is, basically.  Our lifestyles, especially how we move ourselves around, are largely determined by the cities and neighborhoods we live in - the infrastructure.  Income also determines this - whether we can afford a car.  Of course in a larger sense, this is infrastructure too:  who is poor and who is rich is largely determined by the structural makeup of society.

I should also add that this deterministic view is only partially true, in my opinion. We all have some choices, and a variety of factors besides money go into determining where we live and how we live.  In some cities, you don't have a lot of choices, but in some (many?), you can find relatively cheap housing that's close to where you work and shop and play - unless you have prejudices about crime and race and what it takes to feel "affluent". And "cheap" might mean cheap when you factor in the decreased cost of not driving everywhere, but that's a calculation that anyone can do. It's not rocket surgery.  

I'm happy that the city I live in does afford some choices.  I've made the choice to live downtown and bike or walk nearly everywhere, while many live in the foothills and the east side, often because they're afraid of "dirty, shabby" downtown and the brown neighborhoods just to the south and west. (In a way this is infrastructure too, the cultural infrastructure of racism and fear of the other - or is it "superstructure"? maybe I should re-read Marx...)

I'm also happy there's an excellent blog that covers bicycling in Tucson, Tucson Velo, which just reported that the police are doing a plainclothes operation to catch motorists who break the 3-foot rule and drive dangerously close to bicyclists.  Things are progressing, slowly, around here.