The Iowa Dept of Transportation (DOT) currently utilizes the empirically-based American Association of State Highway and Transportation Officials (AASHTO) pavement design procedures originally derived from the 1960 Road Test data. It is clear that these empirical procedures are no longer applicable to current conditions in Iowa. With the release of the new Mechanistic-Empirical Pavement Design Guide (MEPDG) in the USA, there is a big shift in pavement analysis and design and many state highway agencies undertake initiatives to implement the MEPDG. In order to effectively and efficiently transition to the MEPDG and accelerate its adoption, the Iowa DOT needs a detailed implementation and training strategy. In support of the MEPDG implementation initiatives, sensitivity studies were conducted using the MEPDG software to identify design inputs pertaining to both rigid pavements and flexible pavements that are of particular sensitivity in Iowa. This paper is the first of the two companion papers discussing the need for implementing the MEPDG in Iowa, benefits of implementing the MEPDG in Iowa, and the results of rigid pavement input parameter sensitivity analysis. The results of flexible pavement design inputs sensitivity analysis and implementation recommendations are presented in the second paper.