1. Assistant Professor, Dept. of Transportation Engineering, Federal Center for Technological Education of Minas Gerais, 203 José de Oliveira Vaz St., Belo Horizonte, MG 30575-855, Brazil (corresponding author).
2. Professor, São Carlos School of Engineering, Univ. of São Paulo, 400 Trabalhador São-carlense Ave., São Carlos, SP 13566-590, Brazil.