Introduction reference profiles
It is important to implement a standard the correct way. Two committees have made this contribution to ensure correct implementation, CEN/TC 227/WG 5 and ISO/TC 43/SC 1/WG 39. One step in the development of a standard is the implementation. Right now, two standards have a reference program-code and calculated reference data from reference profiles. The variables are IRI (International Roughness Index), WLP (Weighted Longitudinal Profile), and RMS in different wavelength bands (Root Mean Square), roughness indexes, and MPD (Mean Profile Depth), macrotexture. The implementation of IRI, WLP, and RMS have been done within CEN from the standard EN 13036-5:2019 and MPD has been implemented from ISO 13473-1:2019.
IRI, CEN 13036-5
IRI = International Roughness Index
As support for controlling the implementation of the unevenness indices calculation, three longitudinal profiles are available. The profiles represent low, medium, and high unevenness. A true value for each is also available. The longitudinal profiles are 1000 meters long (the start value 0,0 is excluded) and have the vertical unit millimeter. They are available with three-step lengths (acquisition repetition intervals) 0,05 m, 0,1 m and 0,125m. The profiles are embedded in the last page of the downloadable PDF-file below.
The true IRI value is calculated with respective Δx=0,05 m, 0,1 m, and 0,125m and presented as an average per 20 meters. (updated December 2018)
Weighted Longitudinal Profile (WLP)
WLP is a longitudinal evenness index that is defined and described in EN 13036-5:2019, the same standard as explains IRI. A Matlab-program code used for WLP calculations can be found in the standard.
The longitudinal profiles used in the calculations of the reference values are attached to the document “Reference profiles and values for the International Roughness Index” provided by VTI.
The purpose of the present report is to act as a support for those who want to test their own computer code.
Waveband analysis using bi-octave bands and RMS
Waveband analysis using bi-octave bands and RMS can be used to describe the longitudinal evenness. The indexes are defined and described in EN 13036-5:2019, the same standard as explains IRI. A C++ program code for the calculations can be found in the standard.
The longitudinal profiles used in the calculations of the reference values are attached to the document “Reference profiles and values for the International Roughness Index” provided by VTI. The reference values for the output of the program code can be found in the attached files below.
The purpose of reference data is to act as a support for those who want to verify their own computer code or implement the code in the standard.
MPD, ISO 13473-1
Mean Profile Depth = MPD
As support for controlling the implementation of the MPD calculation, eight texture profiles are available. The profiles represent different types of pavements with different levels of MPD, from low to high macrotexture. The texture profiles are 1000 meters long and have a vertical unit millimeter. The first seven profiles have a step length (acquisition repetition interval) of 1 mm and the eighth profile 0.234337194819742 mm. The profiles are available as raw data text files. The program code is written in Matlab and can be found in a PDF-file (mpd_reference_implementation_08.pdf) together with the result of the calculated MPD values presented as 20 m values and the average for the entire section.