CALIBRATION OF ROAD ROUGHNESS MEASURING EQUIPMENT. VOLUME I: EXPERIMENTAL INVESTIGATION. FINAL REPORT

An extensive series of measurements was made of the performance of a particular model of an inertial road profiling system (IRPS), including evaluation of the noncontact height sensors, the accelerometers used to establish the inertial reference frame, the distance encoder, the associated instrumentation, and the software used to convert the raw data into road elevation profiles. A field program was carried out which included rod-and-level surveys of several roads which were also profiled using the IRPS. The IRPS was also equipped with a commercial response-type road roughness measurement (RTRRM) system, with accelerometers to measure the vertical vibration of both the axle and the body of the vehicle, and with a linear potentiometer to measure the relative displacement between the axle and the body of the vehicle. Separate laboratory measurements were made to characterize the performance of the commercial RTRRM. Data collected with the RTRRM and with the auxiliary accelerometers and the linear potentiometer were compared with single-number ratings of road roughness as computed from the profiles measured using the IRPS. This report documents the measurements and analyses that were carried out in order to enable rational development of the calibration and testing procedures that are given in the companion report, FHWA-RD-89-078, Calibration of Road Roughness Measuring Equipment, Volume II: Calibration Procedures.