> If you want a half-decent model, at least look at NYC

I don't have the data, honestly, but isn't NYC (and it's surrounding cities/suburbs) more dense than the Bay Area?

In SF (the city) transpiration is quite decent because it's dense; single family houses and public transpiration together is a very very tricky to pull; you have to choose one or the other and most people would rather live in a family house than an apartment/condo with good transpiration