1. Assoc. Prof., Dept. of Civ. Engrg., Vanderbilt Univ., Box 103, Station B, Nashville, TN 37235
2. Assoc. Prof., Dept. of Geography, Univ. of North Carolina, Chapel Hill, NC 27599‐3220
3. Dir., Transp. Res. Ctr., Arizona State Univ., Tempe, AZ 85287‐6306
4. Asst. Dir., Inst. for Transp. Res. and Education, P.O. Box 17489, Raleigh, NC 27619