This post provides evidence that increasing density (households per acre) does indeed reduce vehicle miles traveled per household. The thing is that what people experience is not vehicle miles per household, it is “traffic” and the inconvenience of parking. So even if driving per person or household decreases, the inconvenience of daily life will still increase until you get to a point where cars are unnecessary for most daily work, school, shopping, and leisure trips. I picture a curve where convenience decreases with density up to a certain point, and then increases again. People who have experienced only the decreasing side of the curve have trouble understanding what it would be like to get over the hump and up the other side. And this plays right into the hands of the highway-oil-auto industrial complex.