ISO 10844:2021

INTERNATIONAL ISO
STANDARD 10844
Fourth edition
2021-12
Acoustics — Specification of test
tracks for measuring sound emitted
by road vehicles and their tyres
Acoustique — Spécification des surfaces d'essai pour le mesurage du
son émis par les véhicules routiers et leurs pneumatiques
Reference number
ISO 10844:2021(E)
© ISO 2021

---------------------- Page: 1 ----------------------
ISO 10844:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 10844:2021(E)
Contents  Page
Foreword .iv
Introduction .v
1 Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Requirements of the test track . 3
4.1 Size and geometry . 3
4.1.1 Size . 3
4.1.2 Slope and step . 4
4.2 Surface properties . 6
4.2.1 Irregularity . 6
4.2.2 Sound absorption . 6
4.2.3 Texture . 7
4.3 Material properties of the drive lane. 7
4.4 Conformity tests . 8
4.5 Break-in of the test track . 9
4.6 Stability with time and maintenance . 9
5  Measurement methods and data processing .10
5.1 Measurement points . 10
5.1.1 Drive lane . 10
5.1.2 Propagation area . 11
5.2 Irregularity measurement method .12
5.3 Texture measurement methods .12
5.3.1 Texture profile measurement and MPD calculations .12
5.3.2 Texture skewness and shape factor (g-factor) calculations (optional) .12
5.3.3 Texture spectrum calculations (optional) .13
5.4 Sound absorption measurement method . 13
5.5 Slope and step measurement methods . 13
5.5.1 Gradient measurement .13
5.5.2 Cross fall measurement . 13
5.5.3 Step measurement . 14
5.6 Aggregate grading measurement method . 14
5.7 Bitumen modification elastic material measurement method. 15
5.8 Surface course thickness measurement method . 15
6  Conformity report .15
7  Summary of improvements on the 2014 edition .17
Annex A (informative) Maintenance and stability of acoustic performance of test surface
over time .18
Annex B (informative) Method of calculation of shape factor (g-factor) .19
Annex C (informative) Improvements to this version compared to ISO 10844:2014 .23
Bibliography .24
iii
© ISO 2021 – All rights reserved

---------------------- Page: 3 ----------------------
ISO 10844:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This fourth edition cancels and replaces the third edition (ISO 10844:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— various revisions to improve track reproducibility;
— reduce ambiguity in the document.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
  © ISO 2021 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 10844:2021(E)
Introduction
In general, the road surface parameters affecting the sound emission of vehicles are the texture and
sound absorption characteristics. In addition, the mechanical impedance and the skid resistance
properties of the surface layer can influence measured sound levels.
In order to minimize the variation in rolling sound emission and vehicle sound emission measurements
made at different testing locations, it is therefore necessary to specify the relevant surface properties
and recommend carefully the properties of the materials, design, and construction of the test surface.
The principal objective of this document is to provide a specification of the surface which improves the
reproducibility of measurement.
This document is designed in a way that test tracks conforming to this document are compatible with
previous editions, but in addition the variability of properties is reduced.
It is important that the test provides a high degree of reproducibility between different test sites and
that the surface design should not only minimize the inter-site variation of tyre or road sound, but should
also ensure that the propagation of sound is unaffected by the surface used. This latter consideration
precludes the use of road surfaces which have open textures and which have the property of absorbing
sound from the power unit and other related sources.
In relation to the previous editions, this document includes more restrictive specifications of the surface
and recommendations for the test track construction process and maintenance. The basic properties of
the surface remain unchanged.
Furthermore, this document recommends a non-destructive test method for periodic checking of the
surface characteristics.
v
© ISO 2021 – All rights reserved

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 10844:2021(E)
Acoustics — Specification of test tracks for measuring
sound emitted by road vehicles and their tyres
1 Scope
This document specifies the essential characteristics of a test track surface intended to be used for
measuring rolling sound emission of vehicles and their tyres.
The surface design given in this document
— produces consistent levels of tyre or road sound emission under a wide range of operating conditions
including those appropriate to vehicle sound testing,
— minimizes inter-site variation,
— limits absorption of the vehicle sound sources, and
— is consistent with road-building practice.
2  Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 362-1, Measurement of noise emitted by accelerating road vehicles — Engineering method — Part 1: M
and N categories
ISO 13472-2, Acoustics — Measurement of sound absorption properties of road surfaces in situ — Part 2:
Spot method for reflective surfaces
ISO 13473-1, Characterization of pavement texture by use of surface profiles — Part 1: Determination of
mean profile depth
ISO 13473-3, Characterization of pavement texture by use of surface profiles — Part 3: Specification and
classification of profilometers
3  Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 362-1, ISO 13473-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
sound absorption
fraction of the sound power incident on the test object that is absorbed within the test object for a plane
wave at normal incidence, expressed as a percentage
3.2  Surface profile
1
© ISO 2021 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 10844:2021(E)
3.2.1
irregularity
maximum variation of a surface from the measurement edge of a straightedge of minimum 3 m,
measured between two contact points of the straightedge when placed perpendicular to the surface
3.2.1.1
longitudinal irregularity
irregularity (3.2.1) in the direction parallel to the longitudinal axis of the track
3.2.1.2
transverse irregularity
irregularity (3.2.1) in the direction parallel to the transverse axis of the track
3.2.2
texture profile
surface profile of a cross-section through a pavement limited to the texture range
Note 1 to entry: The surface profile is as defined in ISO 13473-1.
3.3  Slope and step
3.3.1
gradient
ratio of the height difference to the length measured parallel to the longitudinal axis of the track
Note 1 to entry: The gradient is expressed as a percentage.
3.3.2
cross fall
ratio of the height difference to the length measured parallel to the transverse axis of the track
Note 1 to entry: The cross fall is expressed as a percentage.
3.3.3
step
height difference between the edge of the drive lane and the propagation area
3.4
propagation area
part of the test track on each side of the drive lane
Note 1 to entry: See Figure 1.
3.5
drive lane
part of the test track where the vehicle operates
3.6
dense asphalt concrete
asphalt in which the aggregate particles are essentially continuously graded to form an interlocking
structure
3.7
mean profile depth
average value of the texture profile (3.2.2) depth
Note 1 to entry: The mean profile depth is as defined in ISO 13473-1, expressed in millimetres.
2
  © ISO 2021 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 10844:2021(E)
3.8
heavy vehicle
vehicle category M2 above 3,5 t, M3, N2, and N3
Note 1 to entry: Vehicle categories are as defined in ISO 362-1.
4  Requirements of the test track
4.1  Size and geometry
4.1.1 Size
The test track shall consist of two areas, a drive lane and a propagation area. The dimensions of the
drive lane and propagation areas to be tested in this standard shall comply with Figure 1 and Table 1.
Dimensions in metres
Key
l entrance construction run-up section (diagonal hatch area), in metres
s,1
l exit construction run-up section (diagonal hatch area), in metres
s,2
(length of entrance and exit construction run-up sections can differ)
l entrance drive lane extension beyond propagation area, in metres
a,1
l exit drive lane extension beyond propagation area, in metres
a,2
(length of entrance and exit drive lane extensions can differ)
w drive lane width, in metres
AA' entrance to propagation area 10 m before line PP’
BB' exit from propagation area 10 m after line PP’
CC' drive lane centre line (longitudinal axis)
PP' microphone line (transverse axis)
a
Propagation area.
b
Drive lane.
Figure 1 — Size of the test track
3
© ISO 2021 – All rights reserved

---------------------- Page: 8 ----------------------
ISO 10844:2021(E)
The drive lane shall have a length of 20 m centred around line PP’, plus drive lane extensions on both
ends, each with a minimum length of l as defined in Table 1. The drive lane shall have a minimum width
a
of 3,0 m. The drive lane is not necessarily constructed as a single paved lane. However, this practice is
recommended.
Wheel tracks shall be designated based on the vehicles anticipated to use the track.
NOTE 1 The drive lane width is not necessarily the same as the paved lane width.
Table 1 — Minimum drive lane extension length
For testing long vehicles with rear engine, having
For testing tyres, passenger cars, motor- a distance of more than10 m between the refer-
Length
cycles, light duty vehicles, and trucks ence point and the front axle
(reference point as defined in ISO 362-1)
a
l 10 m 20 m
a
a
20 m is necessary only for the exit side (BB'), as defined in ISO 362-1, of the test track according to the purpose of this
requirement.
For the stabilization of the laying process, a minimum construction run-up section length of l = 60 m is
s
recommended on at least one side.
The propagation area shall extend at least 10 m from the centre of the drive lane (line CC’) and at least
10 m to both sides of the line PP'.
Within a radius of 50 m around the intersection of CC’ and PP’, the space shall be free of large reflecting
objects such as solid fences, bridges, or buildings. Objects suspected to be large reflecting may be
evaluated using appropriate acoustical measurement methods.
NOTE 2 Buildings outside the 50 m radius can have significant influence if their reflection focuses on the test
track.
4.1.2  Slope and step
Conformity for cross fall shall be evaluated separately for the drive lane and propagation area.
Principal requirements for conformity:
— cross fall arithmetically averaged over all measurement intervals shall be equal to or less than the
requirement;
— at least 80 % of all measurement intervals shall have cross fall equal to or less than the requirement;
— gradient arithmetically averaged over all measurement intervals shall be equal to or less than the
requirement;
— at least 80 % of all measurement intervals shall have gradient equal to or less than the requirement;
— absolute value of step arithmetically averaged over all measurement points shall not exceed the
requirement;
— at least 80 % of all measurement points shall have step that does not exceed the requirement.
Requirements for acceptance of the track only:
— drive lane cross fall shall be equal to or less than 1,0 % (see Figure 2);
— drive lane gradient shall be equal to or less than 0,5 %;
— propagation area cross fall shall be equal to or less than 2,0 % (see Figure 2);
4
  © ISO 2021 – All rights reserved

---------------------- Page: 9 ----------------------
ISO 10844:2021(E)
— step from the edge of the drive lane to the propagation area shall not exceed 20 mm down or 5 mm up
(see Figure 3).
The slope and step should be designed in such a way that the draining of water is possible.
Key
1 drive lane 1,0 % maximum
2 propagation area 2,0 % maximum
Figure 2 — Cross fall examples
Dimensions in millimetres
Key
1 drive lane
2 propagation area
a
Step down.
b
Step up.
Figure 3 — Step from drive lane to propagation area
5
© ISO 2021 – All rights reserved

---------------------- Page: 10 ----------------------
ISO 10844:2021(E)
4.2  Surface properties
4.2.1  Irregularity
Conformity for irregularity shall be evaluated separately for the drive lane and propagation area.
Conformity shall be evaluated separately for transverse and longitudinal irregularity measurements.
Principal requirements for conformity include both:
— irregularity arithmetically averaged over all measurement points shall be equal to or less than the
requirement;
— at least 80 % of all measurement points shall have irregularity equal to or less than the requirement.
4.2.1.1  Drive lane
The drive lane shall fulfil the following requirements for acceptance of the track only:
— transverse irregularity equal to or less than 3 mm;
— longitudinal irregularity equal to or less than 2 mm.
The drive lane shall fulfil the following requirements for periodic checking of the track only:
— transverse irregularity equal to or less than 5 mm;
— longitudinal irregularity equal to or less than 5 mm;
— if exclusively used for testing heavy vehicles, transverse irregularity equal to or less than 10 mm;
— if exclusively used for testing heavy vehicles, longitudinal irregularity equal to or less than 10 mm.
4.2.1.2  Propagation area
The propagation area shall fulfil the following requirements for acceptance of the track only:
— transverse irregularity equal to or less than 20 mm;
— longitudinal irregularity equal to or less than 20 mm.
4.2.2  Sound absorption
4.2.2.1  Drive lane
For each individual one-third-octave band from 315 Hz to 1 600 Hz, calculate an arithmetic average
using the sound absorption from all measurement points. The average in each individual one-third
octave band shall be equal to or less than 8 %.
At least 80 % of all measurement points shall have sound absorptions of all one-third-octave bands
equal to or less than 8 %.
4.2.2.2  Propagation area
For each individual one-third-octave band from 315 Hz to 1 600 Hz, calculate an arithmetic average
using the sound absorption from all measurement points. The average in each individual one-third
octave band shall be equal to or less than 10 %.
At least 80 % of all measurement points shall have sound absorptions of all one-third-octave bands
equal to or less than 10 %.
6
  © ISO 2021 – All rights reserved

---------------------- Page: 11 ----------------------
ISO 10844:2021(E)
4.2.3  Texture
The surface of the drive lane shall have
a) an average mean profile depth (MPD) of 0,5 mm ± 0,2 mm, and
b) at least 80 % of all measured sections with an MPD of 0,5 mm ± 0,2 mm.
4.3  Material properties of the drive lane
The surface course of the drive lane shall
a) be dense asphalt concrete,
b) have a thickness greater than or equal to 30 mm, and
c) have an aggregate grading conforming to the aggregate grading envelope requirement in Table 2,
verified using either
— a minimum of one sieve size from each of the six sieve categories (sieve category 1 through 6),
if there is no sieve size in sieve category 2 with an aggregate grading of 100 %, or
— a minimum of one sieve size from sieve category 2 through 6, if there is at least one sieve size in
sieve category 2 with an aggregate grading of 100 %.
The recommended option is an aggregate grading of 100 % for at least one sieve size in sieve
category 2;
d) have no elastic material (rubber, polyurethane, etc.) except for the modification of bitumen that is
less than 1 % of the mass of the total asphalt mixture;
Sealing cracks with elastic material shall be permitted; however, materials and methods of installation
shall be selected to minimize the impact to sound emission measurements.
NOTE 1 Alternative sieve sizes for each category accommodate test standards for aggregate grading which
vary by country.
NOTE 2 Testing for sieve category 1 is not necessary if there is an aggregate grading test result of 100 % for
any of the sieves in sieve category 2.
NOTE 3 Polymer-modified Bitumen (PmB) allows higher temperature operation and reduced surface wear.
Table 2 — Aggregate grading envelope
Sieve size Aggregate grading envelope
requirement
mm
%
Sieve category 1
14,0 100
13,2 100
12,5 100
11,2 100
Sieve category 2
10,0 100
9,5 95 to 100
8,0 86 to 100
6,7 79 to 100
6,3 76 to 100
7
© ISO 2021 – All rights reserved

---------------------- Page: 12 ----------------------
ISO 10844:2021(E)
Table 2 (continued)
Sieve size Aggregate grading envelope
requirement
mm
%
Sieve category 3
5,6 71 to 99
5,0 65 to 95
4,75 63 to 93
4,0 56 to 87
Sieve category 4
2,5 43 to 71
2,36 42 to 69
2,0 38 to 63
1,6 33 to 58
1,25 28 to 52
1,18 27 to 51
1,0 25 to 47
Sieve category 5
0,63 20 to 37
0,60 20 to 36
0,50 18 to 32
0,425 17 to 30
0,315 15 to 25
0,30 15 to 25
0,25 14 to 22
Sieve category 6
0,16 11 to 18
0,15 10 to 18
0,125 9 to 16
0,10 8 to 15
0,080 7 to 13
0,075 7 to 13
0,063 6 to 12
4.4  Conformity tests
a) Requirements shall be checked at the following occasions, and in accordance with Table 3:
1) acceptance of the track, which shall only be evaluated after construction and break-in of the
track according to 4.5, but before vehicle sound emission measurements begin;
2) periodic checking of the track that was previously accepted as conforming to this document or
the previous edition of this document.
NOTE 1 It is not necessary to evaluate an existing track for acceptance using this document if the track has
previously been accepted using the previous edition of this document.
8
  © ISO 2021 – All rights reserved

---------------------- Page: 13 ----------------------
ISO 10844:2021(E)
Table 3 — Periodicity for checking the requirements during acceptance and periodic checking
of the track
For acceptance of the track For periodic checking of the track
Requirements for the track
Propagation  Propagation
Drive lane Drive lane
area area
×
Gradient N.A. N.A. N.A.
(0,5 %)
Slope
× ×
Cross fall N.A. N.A.
(1,0 %) (2,0 %)
×
×
b
Longitudinal irregularity (≤5 or ≤ 10 mm) N.A.
(≤2 mm)
a
×
2 years
×
(≤20 mm)
×
b
Transverse irregularity (≤5 or ≤ 10 mm) N.A.
(≤3 mm)
a
2 years
×
×
c
Texture (MPD) N.A. (0,5 mm ± 0,2 mm) N.A.
(0,5 mm ± 0,2 mm)
a
2 years
×
× ×
Sound absorption (≤8 %) N.A.
(≤8 %) (≤10 %)
a
4 years
Material properties of the drive lane × N.A. N.A. N.A.
×  to be checked
N.A.  not applicable
a
Periodicity (maximum period between checking).
b
5 mm limit; 10 mm limit if track exclusively used for testing heavy vehicles.
c
For test tracks with acceptance evaluated using mean profile depth calculated in conformity with a previous edition of
ISO 13473-1, periodic checking may also be performed in the same way.
4.5  Break-in of the test track
The texture and sound absorption characteristics of the drive lane shall be checked not earlier than
4 weeks after paving or 1 000 vehicle passes after paving is complete.
If the surface is exclusively used for testing heavy vehicles, this break-in is not required.
4.6  Stability with time and maintenance
The test track is a test instrument and shall be protected from damage and be taken care of. The test
track should be used only for sound measurements.
Loose debris or dust which could significantly impact the surface profile shall be removed from the
surface.
Sealing of cracks is acceptable so long as acoustical performance of the test track is not affected.
See Annex A for recommendations.
9
© ISO 2021 – All rights reserved

---------------------- Page: 14 ----------------------
ISO 10844:2021(E)
5  Measurement methods and data processing
5.1  Measurement points
5.1.1  Drive lane
For sound absorption, irregularity, step, and texture measured using a non-continuous measurement
(according to 5.3.1), measurement points shall be selected on the designated wheel tracks along the
length of the drive lane as illustrated in Figure 4.
The first measurement point shall be selected randomly within ±1 m of PP’ in the longitudinal direction.
Additional measurement points shall be located at 5 m intervals from the first measurement point in
the longitudinal direction.
Tracks with more than one designated wheel track shall distribute measurement points among the
designated wheel tracks.
Tracks with more than one designated wheel track shall have additional measurement points selected
for sound absorption and texture, located in all designated wheel tracks at the two 5 m intervals located
within 5 m of PP’ in the longitudinal direction.
If any randomly selected measurement point is not representative of the drive lane surface withi
...