1. Associate Professor, Dept. of Urban Planning, Univ. of Kansas, 1465 Jayhawk Blvd., 311 Marvin Hall, Lawrence, KS 66045-7626.
2. Postdoctoral Fellow, Glenn Dept. of Civil Engineering, 18G Lowry Hall, Clemson Univ., Clemson, SC 29634 (corresponding author).
3. Mays Profesor of Transportation Engineering, Glenn Dept. of Civil Engineering, 216 Lowry Hall, Clemson Univ., Clemson, SC 29634.