🏗️ Calculation of longitudinal evenness indices of road and airfield pavements from a digitized longitudinal profile (wavelength range 0,5–50 m): International Roughness Index IRI — quarter-car simulation at 80 km/h after smoothing with a 250 mm moving average, in mm/m or m/km, recommended section 100 m (IRI100); root mean square RMS and longitudinal profile variance LPV in three wavelength bands; σWLP and ΔWLP from the weighted longitudinal profile, PN-EN 13036-5

Construction PN-EN 13036-5

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN 13036-5:2020-01, in full (our translation of the Polish card text): “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, the root mean square RMS and the longitudinal profile variance LPV from three separate wavelength bands, and the σWLP and ΔWLP indices from the weighted longitudinal profile WLP. The purpose of this document is to provide a standard practice for calculating and reporting pavement evenness from digitized longitudinal profiles. The purpose of this document is also to facilitate the comparison of measurement results obtained with different measuring systems in European countries. This document covers the evenness range of wavelengths from 0,5 m to 50 m. It is noted that both shorter and longer wavelengths can influence driving comfort but are not covered in this document. The quantified pavement evenness indices specified in this document are useful support for pavement management systems and can also be used in acceptance testing of new and old pavements. The indices can be used on rigid, flexible and gravel road pavements. This document does not specify how the pavement profile is measured The indices obtained are portable in the sense that they can be obtained from longitudinal profiles measured with a variety of instruments”. We read the text of the standard in the preview of SIST EN 13036-5:2019 (text of EN 13036-5:2019) from the cover through the foreword, introduction and Clauses 1–9 (page 13); we do not have Annexes A (normative — IRI calculation, quarter-car model parameters) and B–F (example IRI code, RMS and LPV wave band analysis, WLP calculation, implementation check). The earlier downloaded preview of the draft prEN 13036-5:2017 is not the basis of this description.

ACCORDING TO THE TEXT OF EN 13036-5:2019 (foreword, introduction, Clauses 1–9). The standard was prepared by CEN/TC 227 (road materials); approved on 21 July 2019. Introduction: through road/vehicle dynamic interaction and vehicle vibration, profile evenness affects safety (tyre contact forces), ride quality, energy consumption, vehicle wear and pavement durability — it is therefore key information for road maintenance and performance control systems; the wavelength range 0,5–50 m covers most situations for cars (at higher speeds, e.g. on runways and motorways, longer wavelengths can also be important); the wave band procedures are informative, so IRI is preferred for benchmarking; three profiles with “true values” are available for checking the implementation of the calculations (www.erpug.org, Annex F). Scope (Clause 1): mathematical processing of digitized longitudinal profile measurements to produce evenness indices — IRI, RMS and LPV from three wavelength bands and σWLP and ΔWLP from WLP; wavelength range 0,5–50 m; the indices support pavement management systems, can be used for type approval and control of new and old pavements, on rigid, flexible and gravel pavements; the standard does not define from which position on the road the profile should be obtained; the indices are portable between instruments. No normative references. Definitions (Clause 3): among others reporting repetition interval (length of the analysis section), longitudinal evenness — deviation of the longitudinal profile from a straight line in a defined wavelength range, e.g. 0,5–50 m, longitudinal profile — intersection of the pavement surface with a plane perpendicular to it and parallel to the lane direction (usually the profile in a wheel path, recorded every 50 mm or 100 mm), profile measurement length — length of continuous, accurate recording (excluding the lead-in and lead-out of the profilometer), raw profile, resampling, spatial frequency N = 1/λ (formula 1), acquisition repetition interval, wavelength, wheel paths. Calculation of indices (Clause 5): the profile may come from any lateral position in the lane — the standard says only how to calculate the indices; steps: measurement of the profile with identification of start and end points and events (roundabouts, speed bumps, milestones), for benchmarking — preferably sampling every 0,1 m with resampling that does not introduce erroneous energy into the signal, calculation of one or more indices; pre-processing (resampling and filtering) is essential for wave band analysis and recommended to homogenize profiles; for benchmarking, resampling as with the resample function in Matlab is required, for other uses a linear model may suffice; four groups of indices: IRI (Annex A, normative — for international comparisons), energy in three bi-octave bands RMS (Annex C), profile variance LPV in three bands (Annex D), range and deviation of the weighted profile WLP (Annex E). IRI (6.1): an index computed from the profile by simulating a virtual response-type system — a model of a quarter car travelling at 80 km/h; the accumulated suspension motion (Zs and Zu, Figure 3: sprung and unsprung mass, suspension damping and spring rate, tyre spring rate) is divided by the distance travelled; IRI is computed from a single profile; acquisition interval not larger than 125 mm; a vertical sensor resolution of 0,5 mm is suitable for all conditions (smooth roads require finer resolution); the profile has a constant slope between points; the profile is smoothed with a moving average with a base length of 250 mm; the smoothed profile is filtered by the quarter-car simulation with specified parameters at 80 km/h; the accumulated suspension motion is divided by the profile length — IRI has units of slope, e.g. mm/m or m/km. Results (6.2): the evaluation length L is given as a subscript, e.g. IRI20 for L = 20 m; for European benchmarking 100 m is recommended (IRI100); a simulation with other parameters or another speed must not be called IRI. Wave band analysis (Clause 7): the pre-processed profile is split by filters into bands (short, medium, long waves — Figure 4); short waves reflect small undulations significant at low speeds, long waves — undulations affecting ride quality at high speeds; the definition of the bands, filter characteristics and method of deriving the indices must be reported; band-pass or high-pass filters, chosen with minimal distortion (e.g. forward and reverse digital filtering with a measured section extending beyond the assessed profile); two methods: RMS over bi-octave bands (Annex C) and LPV over selected wavelengths (Annex D). WLP (Clause 8): the profile weighted in the frequency domain by a function enhancing short wavelengths and attenuating long ones, split into octave bands, multiplied by pre-factors and summed; characterized by the standard deviation σWLP and range of variation ΔWLP; pre-processing: de-trending by linear regression, resampling every 0,1 m by linear interpolation, high-pass filter attenuating wavelengths longer than 100 m (amplitude of wavelengths above 150 m attenuated by at least 50 %, without phase distortion of wavelengths shorter than 100 m). Reporting (Clause 9): the index is reported per an agreed presentation length — for international benchmarking 100 m, indicated by a subscript; it is recommended to give the geographic position and data of the object, the lateral position of the profile (right or left wheel path; for benchmarking — the outermost wheel path), distance measured, date and time and conditions that could affect the result; further mandatory information is in EN 13036-6; any deviation from EN 13036-5 must be documented.

STATUS (cards as of 02.10.2026). The card of PN-EN 13036-5:2020-01 in the English version (published 16-01-2020, 55 pages, price group U) does not carry the heading “Wycofana” (withdrawn): Building and Construction Sector, KT 212 Road Construction and Maintenance, ICS 17.040.20, 93.080.10, “Introduces: EN 13036-5:2019 [IDT]”. The PKN search for “PN-EN 13036-5” (02.10.2026) shows only this edition.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 02.10.2026). The number 13036-5 appears in 8 records at 8 laboratories: AB 426, AB 1482, AB 1483, AB 1486, AB 1529, AB 1532, AB 1538, AB 1547. In the current scopes on the PCA website (read on 02.10.2026, issues from 11.07.2025 to 09.09.2026) seven laboratories cite “PN-EN 13036-5:2020-01 p. 6” (the IRI clause), AB 426 — “PN-EN 13036-5:2020-01” without a clause; usually in one field with PN-EN 13036-6:2008, the regulation of the Minister of Infrastructure of 01.08.2019 (Dz. U. 2019 item 1643) and the WR-D-64 guidelines. No row is set in bold italics. The “Laboratories” tab searches for entries STARTING WITH “PN-EN 13036-5” and shows 3 laboratories and 3 items (AB 426, AB 1529, AB 1532) — checked with the tab query on the labcoda.pl production server on 02.10.2026; the remaining five are not visible, because in their field the number stands after another document (PN-EN 13036-6 or the regulation).

WHAT THE LABORATORIES TEST (items in the PCA scopes). Road pavements — “longitudinal profiles (unevenness), range (0–20) cm, profilometric method, inertial device — laser profilograph” and “International Roughness Index IRI (calculated)” (AB 1482, AB 1483, AB 1486, AB 1529, AB 1532, AB 1538, AB 1547); “longitudinal and transverse profiles (unevenness), laser method, laser profilograph” and IRI (AB 426). At AB 426 alongside the transverse unevenness index (PN-EN 13036-8), at the other seven alongside layer thickness (PN-EN 12697-36).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Name: a quarter-car simulation result with other parameters or at a speed other than 80 km/h is not IRI. Section: IRI depends on the evaluation length — it must be given as a subscript (IRI20, IRI100); comparing values from different lengths is an error. Profile: an acquisition interval larger than 125 mm, a resolution coarser than 0,5 mm on smooth roads or omission of the 250 mm moving average change the result; the profilometer’s lead-in and lead-out sections are not part of the measurement length. Position: the standard does not specify which wheel path to measure — it must be stated (for benchmarking — the outermost wheel path). Events: speed bumps, roundabouts and interruptions in measurement must be marked, otherwise they inflate the index. Wave bands: resampling and filters chosen without care for distortion introduce erroneous energy; RMS, LPV and WLP are informative and do not replace IRI in comparisons. Wavelength range: wavelengths shorter than 0,5 m and longer than 50 m (important e.g. on motorways and runways) are not covered.

WHAT WE DO NOT GIVE. We do not have Annexes A–F — the quarter-car model parameters, the method of solving the equations, example code, band limits and filter coefficients of RMS and LPV, the WLP weighting function or the control profiles — so we do not give these numbers.

Method principle

A digitized longitudinal pavement profile (elevations every ≤ 125 mm) is smoothed with a 250 mm moving average and passed through a model of a quarter car travelling at 80 km/h; the accumulated suspension motion divided by the section length gives IRI in mm/m or m/km; in addition, the profile is split by filters into wavelength bands (RMS, LPV) or weighted in the frequency domain (WLP).

Applications

• Road pavements — International Roughness Index IRI from the profile of a laser profilograph, 8 laboratories
• Acceptance of new pavements and assessment of the condition of existing ones (pavement management systems)
• Airfield, rigid, flexible and gravel pavements — comparison of results from different profilometers

Key parameters

Standard

Standard number

PN-EN 13036-5:2020-01 (wersja angielska; EN 13036-5:2019 IDT)

Title (PL)

Cechy powierzchniowe nawierzchni drogowych i lotniskowych — Metody badań — Część 5:Określanie wskaźników nierówności podłużnej

Title (EN)

Road and airfield surface characteristics — Test methods — Part 5: Determination of longitudinal unevenness indices

Step-by-step procedure

1. Longitudinal profile

   Measurement with a profilometer, marking the start and end of the measurement length and events (roundabouts, bumps, milestones); without lead-in and lead-out sections. PN-EN 13036-5:2020-01 current (cards as of 02.10.2026).

2. Pre-processing

   Resampling (for comparisons every 0,1 m, as resample in Matlab) and — for wave bands and WLP — filtering; de-trending for WLP.

3. IRI

   Smoothing with a 250 mm moving average, quarter-car simulation at 80 km/h (parameters — Annex A, NOT GIVEN), accumulated suspension motion / section length.

4. Additional indices

   If required, RMS or LPV in three wavelength bands and σWLP and ΔWLP (Annexes C–E, details NOT GIVEN).

5. Report

   Index for the agreed presentation length (for comparisons IRI100), wheel path, position, date, conditions, deviations; data according to EN 13036-6.

Required equipment and apparatus

Health and safety (OHS)

• Profilometer measurements in road traffic — vehicle marking and traffic management according to regulations; the (computational) standard contains no safety warnings
• SUBSTANTIVE NOTE: IRI without the stated evaluation length is not comparable; a simulation with parameters other than in Annex A or at a speed other than 80 km/h is not IRI

Frequently asked questions