Two things, first a poll on CNN, asking how many Americans could get by without a car. Apparently, I say apparently because the poll has changed, but I've been told the results are 17% Yes. I'm shocked they are that high. The fact of the matter is our entire built environment outside of a few places (albeit highly populated places, NYC, DC, Portland, etc.) is predicated on car ownership and auto-oriented development.
Second, is this related article about Mayors requesting financial help for crumbling infrastructure. I've been to too many cities where they have been so sparsely built that there literally is not the tax base to support the amount of roads and subterranean infrastructure to pay to even maintain it, let alone upgrade it to sufficient standards. Ironic that the most "liberal" in terms of land development allowed are the most "conservative" politically, yet these "conservative" communities often have the highest tax rates to support their unsustainable development patterns.
Don't build more densely because I say so, support dense development because it is all we can afford.