Walkable neighbourhoods - the secret for success

A study Retrofitting the Suburbs to Increase Walking  by Marlon G. Boarnet, Kenneth Joh, Walter Siembab, William Fulton, and Mai Thi Nguyen finds that "the number of businesses per acre is the single most robust indicator of whether people are likely to walk in their neighborhood. We find that people living in neighborhoods with more business establishments per acre conduct more of their travel within their neighborhood and are more likely to travel by walking.  

This suggests that walkable neighborhoods are often places where there are many nearby destinations. Measures that might correlate with large establishments—retail employmentorsales—did not predict walking travel nearly as reliably as the number of businesses per acre, suggesting that the key is not simply sales but a large number and variety of businesses in a relatively small area."

http://uctc.net/access/39/access39_suburbwalking.shtml