1. Transportation Engineer in Training, Stantec Consulting Services, Inc., 2000 S Colorado Blvd., Suite 2-300, Denver, CO 80222 (corresponding author).
2. Associate Professor, Dept. of Civil Engineering, 238 Harbert Engineering Center, Auburn, AL 36849-5337.
3. Associate Professor, School of Traffic and Transportation, Beijing Jiaotong Univ., Beijing 100044, China.