walkshed
n.— «Typically, the “walkshed” for transit is about one-quarter mile and, in some cases, as much as one-half mile if sufficient infrastructure is in place to accommodate pedestrians (i.e. sidewalks, safety design and lighting; and land uses that activate the walking environment).» —“Section 5″ by El Dorado County Transportation Commission Folsom El Dorado Corridor Transit Strategy Final Report (Placerville, California) Dec. 9, 2005. (source: Double-Tongued Dictionary)