From the May issue of the Harvard Business Review:
“Recent studies by Frank and others show that as a neighborhood’s overall walkability increases, so does the amount of walking and biking—while, per capita, air pollution and body mass index decrease.”
Not news to anyone who’s followed the discussions here on New Urbanism: If you isolate people in cul-de-sacs, they’ll drive; they have no choice. But put everything within walking distance and driving decreases and walking increases. You won’t have to force people out of cars, because they won’t need them.
The maps in the article even follow the White Flint “robust street network” debate:
The brief article is here: http://hbr.org/2010/05/back-to-the-city/sb1