Blocks in Philadelphia's Center City average 400 to 500 feet, so there are 10.56 to 13.2 Philadelphia city blocks in a mile. The size of blocks is not the same throughout the city. The blocks in Northeast Philadelphia and Northwest Philadelphia tend to be much longer than the blocks in Center City.
In 2008, Walk Score ranked Philadelphia as the fifth most walkable city in the United States, ranking only behind San Francisco, New York, Boston and Chicago. According to Frank Jaskiewicz, a transportation planner at JzTI Transport Planning, Philadelphia's Central City "rates as one of the best American cites, easily, in terms of its walkability."
Shorter city blocks are better for pedestrians than longer blocks, because the shorter blocks give pedestrians more options for routes between their points of departure and their destinations. City blocks that are over 500 feet long push the boundaries of walkability. Other factors that contribute to a city's walkability include street width, crosswalk signal cycles and sidewalk widths. Traffic tends to move more slowly on narrower streets, which is good for pedestrians. Brief signal cycles at crosswalks mean pedestrians do not have to wait as long to cross the street. Wider sidewalks also benefit pedestrians.