1. Assistant Professor, Dept. of Civil and Construction Engineering, Western Michigan Univ., Kalamazoo MI 49008-5316.
2. Research Associate, Advanced Transportation Technology Research Center, Korea Transport Institute, 2311 Daewha-dong, Ilsan-gu, Koyang-shi, Kyunggi-do 411-701, Korea.
3. Professor, Dept. of Civil and Environmental Engineering, and Institute of Transportation Studies, Univ. of California, Irvine, CA 92697-3600.
4. Professor, Dept. of Transportation Engineering, Hanyang Univ., 1271 Sal-dong, Ansan, Kyunggi-do 415-791, Korea.