This report evaluates Minnesota's implementation of a new specification using the International Roughness Index (IRI) for measuring pavement smoothness on new concrete pavements. It reviews smoothness specifications in other states, analyzes the effects of different surface features on IRI and profile index measurements, and makes recommendations to modify Minnesota's 2006 pilot IRI specification. Key findings include that different wavelength features can affect the indices differently and make direct comparison difficult, and that additional study is recommended on the long-term effects of diamond grinding used to achieve smoothness. The researchers provide a recommended modified specification and additional considerations for MnDOT.