1. Postdoctoral Fellow, Glenn Dept. of Civil Engineering, 18 G Lowry Hall, Clemson Univ., Clemson, SC 29634 (corresponding author).
2. Eugene Douglas Mays Professor of Transportation, Glenn Dept. of Civil Engineering, 216 Lowry Hall, Clemson Univ., Clemson, SC 29634.
3. Professor, Dept. of Mathematical Sciences, O-208 Martin Hall, Clemson Univ., Clemson, SC 29634.
4. Associate Professor, Dept. of Urban Planning, 311 Marvin Hall, 1465 Jayhawk Blvd., Univ. of Kansas, Lawrence, KS 66045-7626.