BACKGROUND: Inertial profilers are used by state highway agencies and others to produce a relatively accurate and repeatable measurement of the pavement profile, which can then be analyzed to produce various smoothness statistics (e.g., International Roughness Index—IRI).  AASHTO R 56, Standard Practice for Certification of Inertial Profiling Systems, describes a certification procedure for operators and test equipment used to measure a longitudinal surface elevation profile of a roadway based on an inertial reference system that is mounted on a data collection vehicle.  The practice stipulates minimum requirements intended to address the need for accurate and repeatable profile measurements for construction quality control/quality assurance, acceptance, and network-level data collection.  However, there is a concern that this practice does not adequately address the range of potential applications (e.g., project-level versus network-level data collection and low and high pavement roughness).  Research is needed to identify the shortcomings of R 56, pursue needed work to identify rational modifications, and develop an updated version of R 56 for consideration and adoption by AASHTO.  

OBJECTIVE: The objective of this research is to develop an updated version of AASHTO R 56, Standard Practice for Certification of Inertial Profiling Systems, for consideration and adoption by AASHTO. 

STATUS: Research is complete; the final report has been published as NCHRP Research Report 1057: Enhancement of the Practice for Certification of Inertial Profiling Systems.