Acoustics -- Specification of test tracks for measuring sound emitted by road vehicles and their tyres

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.

Acoustique -- Spécification des surfaces d'essai pour le mesurage du son émis par les véhicules routiers et leurs pneumatiques

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Status
Published
Publication Date
05-Dec-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
28-Oct-2021
Completion Date
27-Oct-2021
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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
© 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
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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.
© 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.
© ISO 2021 – All rights reserved
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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
© ISO 2021 – All rights reserved
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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.

© ISO 2021 – All rights reserved
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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)
Propagation area.
Drive lane.
Figure 1 — Size of the test track
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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

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)
l 10 m 20 m

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

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);

© ISO 2021 – All rights reserved
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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
Step down.
Step up.
Figure 3 — Step from drive lane to propagation area
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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 %.
© ISO 2021 – All rights reserved
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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
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
© ISO 2021 – All rights reserved
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ISO 10844:2021(E)
Table 2 (continued)
Sieve size Aggregate grading envelope
requirement
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.
© ISO 2021 – All rights reserved
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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 %)
Longitudinal irregularity (≤5 or ≤ 10 mm) N.A.
(≤2 mm)
2 years
(≤20 mm)
Transverse irregularity (≤5 or ≤ 10 mm) N.A.
(≤3 mm)
2 years
Texture (MPD) N.A. (0,5 mm ± 0,2 mm) N.A.
(0,5 mm ± 0,2 mm)
2 years
× ×
Sound absorption (≤8 %) N.A.
(≤8 %) (≤10 %)
4 years
Material properties of the drive lane × N.A. N.A. N.A.
× to be checked
N.A. not applicable
Periodicity (maximum period between checking).
5 mm limit; 10 mm limit if track exclusively used for testing heavy vehicles.

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.
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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

...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 10844
ISO/TC 43/SC 1
Acoustics — Specification of test
Secretariat: DIN
tracks for measuring sound emitted
Voting begins on:
2021­09­01 by road vehicles and their tyres
Voting terminates on:
Acoustique — Spécification des surfaces d'essai pour le mesurage du
2021­10­27
son émis par les véhicules routiers et leurs pneumatiques
Member bodies are requested to consult relevant national interests in ISO/TC
22 before casting their ballot to the e­Balloting application.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 10844:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 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
CH­1214 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/FDIS 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 Break­in 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

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ISO/FDIS 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 non­governmental, 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
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ISO/FDIS 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 non­destructive test method for periodic checking of the

surface characteristics.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 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 inter­site variation,
— limits absorption of the vehicle sound sources, and
— is consistent with road­building 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 362­1, Measurement of noise emitted by accelerating road vehicles — Engineering method — Part 1: M

and N categories

ISO 13472­2, Acoustics — Measurement of sound absorption properties of road surfaces in situ — Part 2:

Spot method for reflective surfaces

ISO 13473­1, Characterization of pavement texture by use of surface profiles — Part 1: Determination of

mean profile depth

ISO 13473­3, 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
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ISO/FDIS 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.

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ISO/FDIS 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 run­up 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)
Propagation area.
Drive lane.
Figure 1 — Size of the test track
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ISO/FDIS 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

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)
l 10 m 20 m

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

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);

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ISO/FDIS 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
Step down.
Step up.
Figure 3 — Step from drive lane to propagation area
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ISO/FDIS 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 one­third­octave 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 one­third

octave band shall be equal to or less than 8 %.

At least 80 % of all measurement points shall have sound absorptions of all one­third­octave bands

equal to or less than 8 %.
4.2.2.2  Propagation area

For each individual one­third­octave 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 one­third

octave band shall be equal to or less than 10 %.

At least 80 % of all measurement points shall have sound absorptions of all one­third­octave bands

equal to or less than 10 %.
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ISO/FDIS 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 %, either

— 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
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
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ISO/FDIS 10844:2021(E)
Table 2 (continued)
Sieve size Aggregate grading envelope
requirement
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.
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ISO/FDIS 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 %)
Longitudinal irregularity (≤5 or ≤ 10 mm) N.A.
(≤2 mm)
2 years
(≤20 mm)
Transverse irregularity (≤5 or ≤ 10 mm) N.A.
(≤3 mm)
2 years
Texture (MPD) N.A. (0,5 mm ± 0,2 mm) N.A.
(0,5 mm ± 0,2 mm)
2 years
× ×
Sound absorption (≤8 %) N.A.
(≤8 %) (≤10 %)
4 years
Material properties of the drive lane × N.A. N.A. N.A.
× to be checked
N.A. not applicable
Periodicity (maximum period between checking).
5 mm limit; 10 mm limit if track exclusively used for testing heavy vehicles.

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.
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ISO/FDIS 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), measuremen
...

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