I mean tons of the last 7/10 of a mile is done by old beat up delivery trucks, with much less capacity than 18 wheelers, that idle in traffic or idle double parked in the turning lane. I'm not going to argue that cities aren't more efficient but the picture that city-dwellers (self-satisfied New Yorkers in particular) paint about their environmental and ecological impact tend to be a very narrow window of the overall impact of their choice to live there.