An Empirical Assessment of Pavement Roughness in the US by Panagiotis Ch. Anastasopoulos 1 , Samuel Labi 1 , Matthew Karlaftis 2 , and Fred L. Mannering 1 1 Purdue University, School of Civil Engineering, 550 Stadium Mall Drive, West Lafayette, IN 47907 2 National Technical University of Athens, School of Civil Engineering, Zografou Campus: Heroon Polytechniou 9, 15780 Zografou, Greece January 10, 2009 Presented at the 88 th Annual Meeting of the Transportation Research Board. Washington DC, January 11-15, 2009.