1. Professor, Dept. of Civil Engineering, Northwestern Univ., 2145 Sheridan Rd., Evanston, IL 60208.
2. Assistant Professor, Civil Engineering Dept.-TRAN, Univ. of Texas at Austin, 1 University Station C1761, Austin, TX 78712-0278.
3. Research Professor, Dept. of Civil and Coastal Engineering, Univ. of Florida, 365 Weil Hall, Gainesville, FL 32611-6580.
4. Transportation Planner, Project Analysis and Urban Studies Section, Ohio Dept. of Transportation, 1980 W. Broad St., Columbus, OH 43223.