1. Assistant Professor, Dept. of Transportation Engineering, Federal Center for Technological Education of Minas Gerais, 5253 Amazonas Ave., Belo Horizonte 30421-169, Minas Gerais, Brazil (corresponding author).
2. Professor, São Carlos School of Engineering, Univ. of São Paulo, 400 Trabalhador São-carlense Ave., São Carlos 13566-590, São Paulo, Brazil.
3. Professor, Dept. of Civil and Coastal Engineering, Univ. of Florida, 512-E Weil Hall, Gainesville, FL 32611.