Measurement of International Roughness Index by Using <i>Z</i>‐Axis Accelerometers and GPS

Abstract

The International Roughness Index (IRI) is a well‐recognized standard in the field of pavement management. Many different types of devices can be used to measure the IRI, but these devices are mainly mounted on a full‐size automobile and are complicated to operate. In addition, these devices are expensive. The development of methods for IRI measurement is a prerequisite for pavement management systems and other parts of the road management industry. Based on the quarter‐car model and the vehicle vibration caused by road roughness, there is a strong correlation between the in‐car Z ‐axis acceleration and the IRI. The variation of speed of the car during the measurement process has a large influence on IRI estimation. A measurement system equipped with Z ‐axis accelerometers and a GPS device was developed. Using the self‐designing measurement system based on the methodology proposed in this study, we performed a small‐scale field test. We used a one‐wheel linear model and two‐wheel model to fit the variation of the Z ‐axis acceleration. The test results demonstrated that the low‐cost measurement system has good accuracy and could enhance the efficiency of IRI measurement.