but (hundreds of thousands[living in high density LA]) + (hundereds of thousands [living in high density SF]) + 8 million (living in NYC) =/= 10% * 350 million.

but (hundreds of thousands[living in high density LA]) + (hundereds of thousands [living in high density SF]) + 8 million (living in NYC) =/= 10% * 350 million. In fact, if we generously estimate that 10 million people live in high density metro areas that don't rely on cars we are looking at less than 3% of the US population. I think that is something to sneeze at.