Professor, Department of Civil and Environmental Engineering, Pennsylvania State University, 2013-present. Visiting Scholar, Department of Civil and Environmental Engineering, University of California at Berkeley,
2011-2012. Visiting Research Engineer, Institute of Transportation Studies,
2011-2012. Visiting Research Engineer, Institute of Transportation Studies, University of California at Berkeley, 2013-present. Associate Professor, Department of Civil and Environmental Engineering, Pennsylvania State University,
2004-2013. Graduate Faculty, Operations Research Program, College of Engineering, Pennsylvania State University, 2007-Present. Faculty Affiliate, Protective Technology Center, Pennsylvania State University,
2010-2015. Affiliate Faculty, Department of Civil and Environmental Engineering, University of Washington, Seattle, 2004-2007. Assistant Professor, Department of Civil and Environmental Engineering, University of Washington, Seattle,
1999-2004. Affiliate Assistant Professor, Interdisciplinary PhD Program in Urban Planning, University of Washington, Seattle,
2002-2004. Safety Program Research Manager, Washington State Department of Transportation, Olympia, 1996-1999. Transportation Engineering Consultant, Division Manager and Principal, Seattle, WA, 19891996. Graduate Research Assistant, University of Washington, Seattle, 1993-1996, 1988-1989.