The International Road Roughness Experiment (IRRE) : establishing correlation and a calibration standard for measurements

Road roughness is gaining increasing importance as an indicator of road condition, both in terms of road pavement performance, and as a major determinant of road user costs. This need to measure roughness has brought a plethora of instruments on the market. The International Road Roughness Experiment (IRRE) covered two categories of instruments - profilometers, which measure the longitudinal elevation profile of the road and converts this into a roughness index, and response type road roughness measuring systems (RTRRMS's), which integrate readings of the device into an instrument specific numeric. The analyses demonstrated a good correlation between the RTRRMS's, and between the RTRRMS's and profilometer records, and showed that they could all be calibrated to a single roughness scale without compromising their accuracy.