> Urban centers should be pedestrian only zones augmented with light rail. Define 'urban center' then. 2km x 2km would be the biggest practical patch w/o vehi

> Urban centers should be pedestrian only zones augmented with light rail. Define 'urban center' then. 2km x 2km would be the biggest practical patch w/o vehicular access except emergency services. 10km x 10km? No way.