1. Ph.D. Candidate, Civil and Environmental Engineering, Carnegie Mellon Univ., Pittsburgh, PA 15213 (corresponding author).
2. Hamerschlag University Professor and Department Head, Civil and Environmental Engineering, Carnegie Mellon Univ., Pittsburgh, PA 15213.
3. H. John Heinz Professor, Civil and Environmental Engineering, Engineering Public Policy, Carnegie Mellon Univ., Pittsburgh, PA 15213.