2021 - Netherlands - Assessment of IRI Measurement

The International Roughness Index (IRI) was developed in the 1980s in the United States of America as a way to estimate the longitudinal road roughness in order to be able to evaluate and maintain road infrastructure in an easy and standardized way. It can be determined by driving with a prepared vehicle, often referred to as High Speed Road Profilers (HSRP), over the road, and measuring the difference in suspension in the wheels by using different sensors over time. Nowadays, it is internationally recognized as a valid measurement, both in America and also in Europe, and also the methods for measuring the necessary data and calculating the index from this data are internationally standardized, e.g. how precise and accurate the sensors must be. The company Infrafocus is using a software called Road Doctor from a Finnish company called Roadscanners which provides two methods that both use Inertial Measurement Unit (IMU) data to derive the road profile, instead of measuring it directly with conventional sensors such as a walking stick or a laser. Since it is not exactly fulfilling the requirements of the certified IRI measurement, this method is not applicable in field work. The purpose of this research will be to compare these methods and their results to find out whether the technique used by Infrafocus is still applicable to calculate the IRI.