Field Experiment for Accuracy Verification of the Devices Measuring International Roughness Index in TRUE Project: Five Years Report

Abstract

Abstract A lot of devices measuring the International Roughness Index (IRI) has recently been developed and applied in response to the pavement inspection purposes. Consequently, the accuracy of measured IRIs obtained with different devices on the same road surface has become a practical concern for providing a consistent inspection result. Against this background, the specified non-profit organization Pavement Diagnosis Researchers Group (PDRG) in Japan has undertaken a project regarding the experiment to harmonize and compare Test methods for surface Roughness Under actual road Environment (TRUE project) since 2014. The TRUE project has so far conducted the roughness measuring experiments three times over five years at Hokkaido, Japan. This paper introduces the features of the TRUE project such as participated devices, test site selection, and data recording and reporting procedures. A benchmark testing for obtaining reference profiles is also provided to make the project reliable. In this paper, the results of experiments conducted in the last five years are statistically described as well. Finally, this paper introduces the potential of the TRUE project such as a new device grouping and the accuracy evaluation report for device certification for contributing to further improvement of a device participated in the project.