1. Doctoral Student, Dept. of Urban and Civil Engineering, Tokyo City Univ., 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557, Japan; Shutoko Technology Center, 3-10-11 Toranomon, Minato-ku, Tokyo 105-0001, Japan.
2. Associate Professor, Dept. of Urban and Civil Engineering, Tokyo City Univ., 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557, Japan (corresponding author).
3. Dept. of Maintenance and Traffic Management, Metropolitan Expressway, 1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8930, Japan.