1. Assistant Professor, Dept. of Geography, Central Michigan Univ., 284 Dow Science Blvd., Mount Pleasant, MI 48859 (corresponding author).
2. Associate Professor, Urban and Regional Planning, Univ. of Michigan, 2225B Art and Architecture Building, 2000 Bonisteel Blvd., Ann Arbor MI 48109-2069.
3. Research Scientist, Univ. of Michigan Transportation Research Institute; and Adjunct Professor, Urban and Regional Planning, Univ. of Michigan, 2901 Baxter Rd., Ann Arbor, MI 48109-2150.