TORSIONAL SAFETY OF HIGHWAY TRAFFIC SIGNAL AND SIGNAGE SUPPORT FINAL PROJECT REPORT by Andre R. Barbosa, Armin W. Stuedlein, and Qiang Li Civil and Construction Engineering Oregon State University Sponsorship PacTrans Oregon Department of Transportation for Pacific Northwest Transportation Consortium (PacTrans) USDOT University Transportation Center for Federal Region 10 University of Washington More Hall 112, Box 352700 Seattle, WA 98195-2700 In cooperation with US Department of Transportation-Research and Innovative Technology Administration (RITA)