Advantages and Limits of Different Road Roughness Profile Signal-Processing Procedures Applied in Europe

Abstract

Three road profile signal-processing methods that give parameters or indices used for the detection of road unevenness in Europe are compared: international roughness index (IRI) analysis, power spectral density analysis, and constant percent bandwidth spectrum analysis. This comparison is carried out with road rideability prediction models, car vibration prediction models, and careful diagnosis and definition of rehabilitation work. The IRI meets the profiling needs with regard to the assessment of road condition, the road serviceability level, and the setting of priorities for planning for road maintenance and repair. This index is not suitable for specification of rehabilitation work or for diagnosis of possible problems with road sections. Power spectral density (PSD) analysis by the International Organization for Standardization’s Standard 8608 is a suitable method with regard to the evaluation of evenness level only if, on the basis of the averaging length, the road profile can be considered a stationary stochastic process and if a single regression line can be fitted. PSD is valuable for the detection of periodic defects in the road profile. Constant percent bandwidth spectrum analysis of consecutive segments along the section under investigation is well adapted to both the road serviceability evaluation and the diagnosis of possible problems with road sections.