One of the major differences is that in the city we walk to get somewhere, but in the suburbs we walk to walk — because there are few errands we can run on shank's mare. For that reason, the long-distance suburban walker, the one who dares hoof it along a major road, can be suspect. This is true for people of all races.
In his book The Lost Art of Walking, Geoff Nicholson tells the story of a well-dressed man stopped by a sheriff's patrol car on the one-mile walk to his office in Los Angeles County. It was on "a completely empty stretch of suburban sidewalk, at midday," the man explained, and he was dressed in a coat and tie when he was ordered to identify himself and explain where he was going. "As a pedestrian," the man said, "I was suspect."
According to his definition (minus the coat and tie), I'm suspect, too.