1. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Virginia, Thornton Hall, P.O. Box 400259, Charlottesville, VA 22904 (corresponding author).
2. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Virginia, Thornton Hall, P.O. Box 400259, Charlottesville, VA 22904.
3. Associate Director, Safety, Operations, and Traffic Engineering, Virginia Transportation Research Council, 530 Edgemont Rd., Charlottesville, VA 22903.