Cities designed to facilitate walking
It seems clear that for reasons of both sustainability and sociability, human power as a means of locomotion in the city should be optimized. Cities designed to facilitate walking will—because of their accessible dimensions—likely be more neighborhood-focused and compact as well as more mixed in use. To be reached by walking, a destination—whether a school, office, or shop—must be close at hand. A reasonable walking time (in this culture) for basic necessities is generally considered to be about ten minutes, which translates (at an average walking speed of three to four miles per hour) into six to eight short blocks (or three to four long ones). Using this dimension as a radius, we might begin to think of a comfortable scale for a neighborhood as ten to fifteen New York City blocks.