Development of Methods and Specifications for the Use of Inertial Profilers and the International Roughness Index for Newly Constructed Pavement

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 International Roughness Index (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 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 provided by inertial profilers. The process of developing a draft specification included developing the following: pay factor tables, the methodology for calculating the smoothness bonus, the methodology for locating areas of localized roughness, and inertial profiler certification procedures.