This document specifies the mathematical processing of digitized longitudinal profile measurements to produce evenness indices. The document describes the calculation procedure for the International Roughness Index (IRI), Root Mean Square (RMS) and Longitudinal Profile Variance (LPV) from three separate wavelength bands and the sWLP and ?WLP from the Weighted Longitudinal Profile (WLP).
The purpose of this document is to provide a standard practice for calculating and reporting estimates of road evenness from digitized longitudinal profiles. Other aims with this document are to facilitate the comparison of evenness measurement results carried out with different profiling instruments in European countries.
The evenness range covered in this document is defined as the wavelength range 0,5 m to 50 m. It is noted that both shorter and longer wavelengths can also influence the driving comfort but those are not covered in this document.
The quantified evenness indices derived from this document are useful support for pavement management systems. The output can also be used for type approval and performance control of new and old pavements. The indices can be used on rigid, flexible and gravel road surfaces.
This document doesn’t define from what position on the road the longitudinal profile should be obtained.
The derived indices are portable in the sense that they can be obtained from longitudinal profiles measured with a variety of instruments.