I think the study may be rated based on all their criteria vs population. That might explain why cities with decent public transportation & tons of people rate better. There are just less people in cars compared to the overall population.

In fact, that might explain my area...especially if they count winter driving. We don't have much population, we do have TONS of cars, and no one here has any clue how to drive in the winter. It amazes me how BAD the drivers get when the weather goes sour!