1. Professor, Dept. of Transportation Technology and Management, National Chiao-Tung Univ., 1001, Ta Hsueh Rd., Hsinchu, Taiwan 30050, ROC (corresponding author).
2. Doctoral Student, Dept. of Transportation Technology and Management, National Chiao-Tung Univ., 1001, Ta Hsueh Rd., Hsinchu, Taiwan 30050, ROC.