The Indiana Department of Transportation (INDOT) is currently utilizing a profilograph and the profile index for measuring smoothness assurance for newly constructed pavements. However, there are benefits to implementing a new IRI based smoothness specification utilizing road profiles measured using inertial profilers. Technological advancements have improved the quality of road profiles measured using inertial profilers; furthermore, utilizing inertial profilers allows smoothness data to be collected much more quickly and efficiently than the methodology currently utilized by INDOT. Pavement smoothness quantified using International Roughness Index (IRI) calculated using profiles provided by inertial profiles is better correlated to user response than what is currently being utilized by INDOT. Furthermore, INDOT currently utilizes IRI to monitor the pavement smoothness throughout the remaining life of the pavement. Consequently, Utilizing IRI for measuring the smoothness of newly constructed pavements allows seamless monitoring of pavement smoothness from cradle to grave. This study presents an IRI based draft smoothness specification for newly constructed pavements utilizing profiles provide by inertial profilers. The process developing a draft specification included developing pay factor tables, developing the methodology for calculating the smoothness bonus, developing methodology for locating areas of localized roughness, and developing inertial profiler certification procedures.

Report Number



pavement smoothness, IRI, specification, inertial profiler

SPR Number


Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of this Version