1. Postdoctoral Research Associate, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin at Milwaukee, P.O. Box 784, Milwaukee, WI 53201-0784.
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin at Milwaukee, P.O. Box 784, Milwaukee, WI 53201-0784 (corresponding author).
3. Researcher, Traffic Operations and Safety Laboratory, Univ. of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706.
4. Ph.D. Student, Dept. of Civil Engineering and Mechanics, Univ. of Wisconsin at Milwaukee, P.O. Box 784, Milwaukee, WI 53201-0784.