"Walk Score calculates the walkability of an address [in the U.S.] by locating nearby stores, restaurants, schools, parks, etc. Walk Score measures how easy it is to live a car-lite lifestyle -- not how pretty [or safe] the area is for walking." The site also "ranks 2,508 neighborhoods in the largest 40 U.S. cities to help you find a walkable place to live." San Francisco ranks first; Los Angeles is ninth. Includes maps.