Apropos of some recent coverage of the automotive-traffic troubles and excellent bike commuting in the Twin Cities, a quote from a recent A Word a Day post:
A city that outdistances man's walking powers is a trap for man. - Arnold Toynbee, historian (1889-1975)
Then you have Portland, Oregon, a medium-sized city where two people can comfortably survive without a car. (Let's seem them try that with kids, though!)