Walkable Streets Are More Economically Productive
This is something that certain cities have understood for many years.  Chicago, for example, mandates that all new development from a simple three-story building to a 100-story skyscraper has retail at its base to improve the walkability of its streets and make its business corridors vibrant.  This also helps push down retail rents even in the CBD, allowing local upstart businesses a shot at reaching the masses.<p>Chicago has also come around to the notion that streets aren't "for cars."  Streets are public property and belong to all of the city's citizens, including the hundreds of thousands who don't own a car.  CDOT evaluates streets and sometimes decides that private property storage (parking cars) isn't the best use for some of that land.  So it turns parking spaces into miniature parks or seating areas, or public art.