1. Department of Transportation Engineering, Ajou University, Suwon, South Korea.
2. Institute of Transportation Studies, University of California, Irvine, 4000 Anteater Instruction and Research Building, Irvine, CA 92697-3600.
3. Transportation Engineering, School of Engineering and Technology, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand.