ISO 10542-1:2001
(Main)Technical systems and aids for disabled or handicapped persons — Wheelchair tiedown and occupant-restraint systems — Part 1: Requirements and test methods for all systems
Technical systems and aids for disabled or handicapped persons — Wheelchair tiedown and occupant-restraint systems — Part 1: Requirements and test methods for all systems
Assistances et aides techniques pour les personnes invalides ou handicapées — Systèmes d'attache du fauteuil roulant et de retenue de l'occupant — Partie 1: Exigences générales et méthodes d'essai pour tous les systèmes
General Information
Relations
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 10542-1
First edition
2001-07-15
Technical systems and aids for disabled or
handicapped persons — Wheelchair
tiedown and occupant-restraint systems —
Part 1:
Requirements and test methods for all
systems
Assistances et aides techniques pour les personnes invalides ou
handicapées — Systèmes d'attache du fauteuil roulant et de retenue de
l'occupant —
Partie 1: Exigences générales et méthodes d'essai pour tous les systèmes
Reference number
ISO 10542-1:2001(E)
© ISO 2001
---------------------- Page: 1 ----------------------
ISO 10542-1:2001(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be
edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file,
parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2001
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, elec-
tronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's mem-
ber body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
©
ii ISO 2001 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 10542-1:2001(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Design requirements . 6
5 Identification, labelling, instruction and warning requirements . 8
6 Performance requirements . 13
7 Test reports . 16
Annexes
A Test method for frontal impact . 17
B Measurement of WTORS belt lengths and geometry . 22
C Test for webbing slippage at adjustment devices of wheelchair tiedown straps. 25
D Test method for partial engagement . 27
E Surrogate wheelchair specifications. 28
F Recommendations for design, performance and documentation. 33
G Information sources . 38
Bibliography. 40
©
ISO 2001 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 10542-1:2001(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 10542 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 10542-1 was prepared by Technical Committee ISO/TC 173, Technical systems and aids
for disabled or handicapped persons, Subcommittee SC 1, Wheelchairs.
ISO 10542 consists of the following parts, under the general title Technical systems and aids for disabled or
handicapped persons — Wheelchair tiedown and occupant-restraint systems:
— Part 1: Requirements and test methods for all systems
— Part 2: Four-point strap-type tiedown systems
Annexes A, B, C, D and E form a normative part of this part of ISO 10542. Annexes F and G are for information only.
©
iv ISO 2001 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 10542-1:2001(E)
Introduction
Providing effective protection for the wheelchair-seated occupant of a motor vehicle usually requires that equipment
be installed to secure the wheelchair and restrain the occupant of the wheelchair. ISO 10542 is applicable to this
motor-vehicle adaptive equipment, which is referred to as wheelchair tiedown and occupant restraint systems
(WTORS). The requirements and test methods of this part of ISO 10542 apply to all WTORS that use belt-type
occupant-restraint systems. Additional parts of ISO 10542 will address specific types of WTORS, or deal with
particular applications, and will supplement and/or modify the requirements of this part of ISO 10542. If an additional
part of ISO 10542 exists for a particular type of WTORS, this part of ISO 10542 is not to be used alone for that
WTORS.
This part of ISO 10542 places particular emphasis on design requirements, test procedures, and requirements with
regard to the performance of WTORS in a frontal impact. Performance of WTORS used with rear-facing wheelchairs
involved in frontal impacts, performance of WTORS in rear, side and rollover impacts, and performance of WTORS
used with wheelchair-seated children, may be addressed in future versions of this part of ISO 10542 and its
additional parts. Transportation-related requirements for wheelchairs that are suitable for occupant seating during
motor-vehicle transportation are specified in ISO 7176-19.
The use of only a pelvic belt as an occupant restraint is unlikely to provide adequate safety to a wheelchair user in
the event of a frontal impact. Therefore, this part of ISO 10542 only includes test set-ups and procedures for
occupant restraints that incorporate both a pelvic and an upper torso restraint.
©
ISO 2001 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 10542-1:2001(E)
Technical systems and aids for disabled or handicapped persons —
Wheelchair tiedown and occupant-restraint systems —
Part 1:
Requirements and test methods for all systems
1 Scope
This part of ISO 10542 specifies test methods and requirements for design and performance, for instructions and
warnings to installers and users, and for product marking and labelling for wheelchair tiedown and occupant-restraint
systems (WTORS). It applies to all WTORS that use belt-type occupant restraints that are intended for adult-
occupied wheelchairs used as forward-facing seats by passengers and drivers of motor vehicles.
This part of ISO 10542 applies primarily to complete WTORS, but other parts of ISO 10542 can also be applied to
components and subassemblies sold separately and for replacement parts.
This part of ISO 10542 applies to WTORS intended for use with all types of manual and powered wheelchairs
intended for use by adults, including three- and four-wheeled scooters.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 10542. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 10542 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated references,
the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of
currently valid International Standards.
ISO 3795, Road vehicles, and tractors and machinery for agriculture and forestry — Determination of burning
behaviour of interior materials.
ISO 6487, Road vehicles — Measurement techniques in impact tests — Instrumentation.
UN/ECE R 16, Uniform provisions concerning the approval of safety belts and restraint systems for adult occupants
of power-driven vehicles, Revision 3, Amendment 3, 27 February 1996.
FMVSS 209, Standard No. 209; Seat belt assemblies. Federal Motor Vehicle Safety Standards, 49 CFR
part 571.209, 1 October, 1992.
3 Terms and definitions
For the purposes of this part of ISO 10542, the following terms and definitions apply.
3.1
adult
person having a mass greater than 36 kg
©
ISO 2001 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 10542-1:2001(E)
3.2
airbag
inflatable restraint system
supplementary restraint system
supplemental occupant-restraint system, consisting primarily of a sensor or sensors, diagnostics, inflator(s) and
module(s), which inflates a bag in certain vehicle crashes to assist in preventing the occupant(s) from impacting the
interior portions of the vehicle
3.3
anchor point
point (area) on a vehicle interior component, floor, or wall, wheelchair or wheelchair tiedown, to which an anchorage
is attached
3.4
anchorage
assembly of components and fittings by which loads are transferred directly from the wheelchair tiedown to the
vehicle, or from the occupant restraint to the vehicle, wheelchair, wheelchair tiedown or vehicle interior component
3.5
anthropomorphic test device
ATD
articulated physical analogue of a midsize male used to represent a wheelchair occupant in a test
3.6
automatic-locking retractor
belt retractor incorporating adjustment by means of a positive, self-locking mechanism which is capable of
withstanding occupant-restraint forces
3.7
back restraint
device or system intended to limit rearward movement of an occupant during an impact by providing support to the
back of the torso
3.8
belt
length of webbing material used as part of an occupant restraint or postural support
3.9
emergency-locking retractor
belt retractor incorporating a locking mechanism that is activated by vehicle acceleration, deceleration, or rate of
webbing movement relative to the vehicle, and that is capable, when locked, of withstanding occupant-restraint forces
3.10
end fitting
anchorage or securement hardware to which wheelchair-tiedown or occupant-restraint webbing is fastened, that
attaches directly to an anchor point or to the securement point on the wheelchair
3.11
excursion
horizontal movement of an ATD or wheelchair target relative to its initial position on an impact sled during a test
3.12
fastener
device used to physically secure hardware components and parts in place
NOTE These include, but are not limited to, bolts, nuts, screws, pins and rivets.
©
2 ISO 2001 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 10542-1:2001(E)
3.13
forward-facing
orientation in which the wheelchair-seated occupant faces the front of the vehicle, with the wheelchair reference
�
plane within 10 of the longitudinal axis of the vehicle
3.14
four-point tiedown
wheelchair tiedown system that attaches to the wheelchair frame at four separate securement points and also
attaches to the vehicle at four separate anchor points
3.15
four-point strap-type tiedown
a four-point tiedown that uses four strap assemblies to secure the wheelchair in the vehicle
3.16
harness
occupant-restraint assembly consisting of at least one belt designed to provide pelvic restraint and two belts that
restrain the upper torso by applying forces to both shoulders
3.17
head restraint
device intended to limit rearward displacement of the occupant's head
3.18
impact simulator
device for decelerating, accelerating, or a combination of decelerating and accelerating a section of a vehicle or
assembly of simulated vehicle structures, including instrumentation for measuring data required by this part of
ISO 10542
3.19
impact sled
part of an impact simulator to which components can be mounted for impact testing
3.20
occupant restraint
system or device intended to restrain a motor-vehicle occupant during an impact in order to prevent ejection, and
prevent or minimize contact with the vehicle interior components and other occupants
3.21
pelvic restraint
pelvic belt
lap belt
lap restraint
lower torso restraint
belt-restraint assembly intended to limit movement of the pelvis
3.22
point P
reference point that lies at the cross-sectional centre of a cylinder of diameter 100 mm and length 200 mm,
positioned with the longitudinal axis perpendicular to the wheelchair reference plane such that the curved surface of
the cylinder contacts the backrest and the upper surface of the seat
SeeFigure1.
3.23
postural support
postural belt
component or belt used to support a person in a desired seated position, but not intended to provide occupant
restraint ina vehicleimpact
©
ISO 2001 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 10542-1:2001(E)
Dimensions in millimetres
Key
1 Cylinder, diameter 100 mm
a
Wheelchair reference plane
b
Wheelchair ground plane
Figure 1 — Wheelchair reference point P and wheelchair reference plane
3.24
securement hardware
components of a wheelchair tiedown that attach to the wheelchair
3.25
securement points
points on the wheelchair to which wheelchair tiedowns are connected
NOTE Securement points may be located on hardware components that are permanently or temporarily fastened to the
wheelchair.
3.26
strap
length of webbing material used in a wheelchair tiedown
3.27
surrogate wheelchair
SWC
rigid, reusable device that conforms to the requirements of annex E and that is used to simulate a wheelchair for the
purpose of testing wheelchair-tiedown and occupant-restraint systems
3.28
three-point restraint
three-point belt
occupant-restraint assembly comprised of both a pelvic belt and a diagonal shoulder belt that connect together near
the hip of the user
SeeFigure2.
©
4 ISO 2001 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 10542-1:2001(E)
Key
1 Diagonal shoulder restraint
2 Pelvic restraint
Figure 2 — Three-point belt
3.29
two-point restraint
two-point belt
belt-type occupant-restraint assembly comprised of a single length of webbing and related hardware that anchors at
both ends
SeeFigure3.
Figure 3 — Two versions of a two-point belt restraint: a two-point shoulder belt and a two-point pelvic belt
3.30
upper-torso restraint
shoulder belt
diagonal belt
diagonal restraint
chest harness
portion of an occupant restraint intended to limit movement of the chest and head by application of restraint forces to
the shoulders and chest
©
ISO 2001 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO 10542-1:2001(E)
3.31
webbing
woven material, usually made from nylon or polyester yarn, used in belt and strap assemblies of occupant restraints
and wheelchair tiedowns
3.32
webbing guide
hardware loop or ring anchored to a structural member in the vehicle or wheelchair back, through which an occupant-
restraint belt passes, and changes direction, along the path to the vehicle anchor point
3.33
wheelchair ground plane
plane representing the surface on which the wheelchair rests
SeeFigure1.
3.34
wheelchair reference plane
vertical plane in the longitudinal centreline of the wheelchair
SeeFigure1.
3.35
wheelchair-tiedown and occupant-restraint system
WTORS
complete restraint system for wheelchair-seated occupants comprised of equipment for wheelchair tiedown and a
belt-type occupant restraint
3.36
wheelchair tiedown
wheelchair securement
device or system designed to secure a forward-facing wheelchair in place in a motor vehicle
4 Design requirements
4.1 WTORS
WTORS shall
a) be for use with only one wheelchair and one occupant at a time, and
b) include a belt-type occupant restraint, either by specifying use of the belt restraint and anchorages provided with
the vehicle, or by providing a belt-type occupant restraint with the wheelchair tiedown as part of a complete
WTORS,
c) not require components of wheelchair tiedowns and occupant restraints to pass through the wheels of a
wheelchair,
d) not require removal of wheelchair frame material, drilling into the wheelchair frame, deformation of the
wheelchair, welding, or use of an adhesive process during installation,
e) once installed, be operable without tools,
f) incorporate features to prevent unintentional loosening of all fasteners,
g) have all small manually detachable hardware and fittings tethered to WTORS subassemblies, and
h) include a manual override in case of power failure for any power-operated tiedown or restraint.
Specification of a vehicle-equipped belt-restraint system is primarily for situations in which the WTORS is intended
for use by drivers but, even in this situation, it is recommended that the WTORS manufacturer provide a complete
system, including both wheelchair tiedown and occupant restraint, for after-market installation in the vehicle.
©
6 ISO 2001 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 10542-1:2001(E)
4.2 Wheelchair tiedowns
Wheelchair tiedowns and tiedown components shall
a) not release if any wheelchair component deforms, or if one or more tyres deflate during a vehicle impact,
b) include a means to minimize vehicle-induced movement of the wheelchair that does not require the use of tools,
c) not depend on the wheelchair brakes, and
d) not utilize the occupant restraint to secure any portion of the wheelchair.
4.3 Belt-type occupant restraints provided by the WTORS manufacturer
4.3.1 Occupant restraints provided by the WTORS manufacturer shall
a) have both pelvic and upper torso belts designed to apply forces to the occupant's skeletal regions,
b) function independently of the wheelchair, such that the restraint belts anchor to either the vehicle or wheelchair
tiedown components so that occupant-restraint loads are not transmitted through the wheelchair,
c) have belt restraints that can be adjusted in length without the use of tools.
NOTE WTORS designed with occupant restraints that transfer occupant-restraint loads through the wheelchair require special
labelling and will be dealt with in a future part of ISO 10542.
4.3.2 When set up and measured in accordance with annex B, occupant restraints provided by the WTORS
manufacturer shall
a) produce rear-view projected angles of the pelvic belt within the zones shown in Figure 4,
� �
b) produce side-view projected angles of the pelvic belt between 30 and 75 to the horizontal, as shown in
Figure 4,
c) provide for a range of adjustment of the pelvic restraint that allows for increasing and decreasing the total belt
length by 200 mm from the nominal setup conditions, with at least 25 mm of webbing extending through any
fitting where adjustment takes place,
d) provide for a range of adjustment in the upper-torso restraint that allows for increasing the length by 200 mm, and
shortening the length by 300 mm, from the nominal setup conditions, with at least 25 mm of webbing extending
through any fitting where adjustment takes place, when tested in accordance with annex B, and
e) have the junction of the shoulder and pelvic belts of three-point belt restraints located not less than 150 mm from
the ATD centreline.
4.3.3 If occupant restraints include structural components for the attachment of upper anchorages or guides for
upper torso belts, locations for the upper anchor points shall be provided that are
a) adjustable in height so they can be positioned at or above the shoulder level of the intended user(s), or that are
b) located at least 1 100 mm above the wheelchair ground plane.
4.3.4 Occupant restraints shall
a) only use an airbag for supplementary restraint in conjunction with a wheelchair tiedown and belt-type occupant
restraint that conform with the requirements of this part of ISO 10542, and
b) not depend on an airbag in order to conform with the performance requirements of this part of ISO 10542.
©
ISO 2001 – All rights reserved 7
---------------------- Page: 12 ----------------------
ISO 10542-1:2001(E)
Dimensions in millimetres
NOTE Angles indicated are obtained by projecting the angle of the pelvic belt onto a vertical plane that is parallel to (side view)
or perpendicular to (rear view) the wheelchair reference plane.
a
Wheelchair reference plane
Figure 4 — Range of required angles for pelvic belts and locations of pelvic-belt anchor points
5 Identification, labelling, instruction and warning requirements
5.1 Identification and labelling
5.1.1 WTORS and replacement parts shall be permanently and legibly marked showing
a) manufacturer's name or trademark,
b) month and year of manufacture, and any other identification necessary to clearly identify a WTORS in the event
of a product recall, and
c) that it conforms with ISO 10542-1.
5.1.2 Primary WTORS components and subassemblies shall be accompanied by information that includes
a) manufacturer's model and part number or an equivalent identification code, and
b) the name and intended use of each detachable WTORS component (e.g. right-rear tiedown, shoulder belt, pelvic
belt, etc.).
5.2 Instructions for installers
5.2.1 Manufacturers of WTORS shall provide written instructions for the installer in the principal language(s) of the
country in which it is marketed.
5.2.2 The instructions shall include statements that
a) the WTORS should be installed for forward-facing wheelchairs,
b) identify the number of separate packages containing WTORS components,
©
8 ISO 2001 – All rights reserved
---------------------- Page: 13 ----------------------
ISO 10542-1:2001(E)
c) the WTORS conforms with ISO 10542-1,
d) indicate the minimum specifications for all wheelchair tiedown and occupant- restraint anchorage fasteners and
related components,
e) identify any components to be permanently fastened to the wheelchair, and
�
30
f) indicate that the pelvic-restraint anchor points should be positioned to achieve belt angles of or greater to the
� �
horizontal, and preferably between 45 and 75 to the horizontal, in order to fit low across the pelvis and/or over
the upper thighs and thereby reduce the possibility of the belt loading the abdomen.
5.2.3 The instructions shall include descriptions of
a) any wheelchair features that are required to allow correct fitting of WTORS components that are to be
permanently fastened to the wheelchair,
b) procedures for attaching any components to be permanently fastened to the wheelchair,
c) how the WTORS is to be used, so that the installer may be fully informed regarding the purpose and function of
all components and how they should be installed,
d) the location points of upper anchorages or webbing guides of shoulder and harness restraints, and an
explanation that these points should be selected so that the belt webbing fits near the midpoint of occupants'
shoulders and so that the height is at or above the shoulder heights of intended users, so as to minimise
downward loads on the spine, and
e) minimum vehicle-strength recommendations at all WTORS anchor point locations.
5.2.4 The instructions shall include diagrams and drawings that illustrate
a) acceptable methods for fastening WTORS anchorages to the vehicle, along with minimum strength requirements
forallWTORSanchorpoints,
b) an exploded-view drawing and a parts list for all components required in the installation,
c) the locations for anchor points of independent belt restraints relative to wheelchair tiedown anchor points, along
with the information in Figure 5,
d) distances between WTORS' anchor points and vehicle interior components, including the information in Figure 6.
5.2.5 The instructions shall include warnings that
a) the WTORS be installed by an experienced technician,
b) both pelvic and upper-torso restraints be installed to reduce the possibility of head and chest impacts with vehicle
interior components, and that
c) vehicle anchor points may require reinforcement,
d) additional vehicle interior padding should have a burning rate that does not exceed 100 mm/min when tested in
accordance with ISO 3795,
e) a vehicle-anchored back restraint be provided if a head restraint is anchored to the vehicle, in order to minimize
rearward deflection of the wheelchair seatback and the potential for neck injury,
f) the WTORS not be installed in a manner that may block deployment of an airbag,
g) an airbag be used only as a supplementary occupant restraint in conjunction with a wheelchair tiedown and belt-
type occupant restraint,
h) it is important to locate the wheelchair anchor points properly with respect to the anchor points of the upper and
lower torso belts to achieve good belt-fit geometry,
i) the WTORS manufacturer be consulted in case of questions as to the method of installation on the wheelchair
and/or in the vehicle,
j) alterations or substitutions to the WTORS components should not be made without consulting the WTORS
manufacturer,
k) webbing be protected from contacting sharp corners and edges, and potential corrosive liquids,
l) the extent of head and chest excursions also depends on the location of the upper-torso belt anchor points and
may increase as anchor-point distance above and behind the occupants shoulder increases.
©
ISO 2001 – All rights reserved 9
---------------------- Page: 14 ----------------------
ISO 10542-1:2001(E)
Dimensions in millimetres
a
Wheelchair reference plane
Figure 5 — Preferred and optional angles for pelvic restraints
5.3 User and maintenance instructions
5.3.1 Manufacturers shall provide written instructions for the use and maintenance of the WTORS in the principal
languages of the country in which it is marketed.
5.3.2 The instructions shall include statements that
a) the WTORS conforms with ISO 10542-1,
b) care should be taken to prevent contamination of the webbing with polishes, oils and chemicals, particularly
battery acid, along with procedures and materials to be used for cleaning parts of the WTORS,
c) frayed, contaminated or damaged webbing, and broken or worn parts should be replaced,
d) webbing should be protected from contacting sharp corners and edges, and
e) occupant restraints should be adjusted to fit the user, and that:
1) both pelvic and upper-torso restraints should be used to reduce the possibility of head and chest impacts with
vehicle components,
2) the extent of head and chest excursions also depends on the location of the upper-torso belt anchor points
and may increase as anchor-point distance above and behind the occupants shoulder increases,
3) the pelvic belt should be worn low across the front of the pelvis so as to bear upon the bony structure of the
body, with any junctions between the pelvic and shoulder restraints located near the wearer's hip,
� �
4) the angle of the pelvic belt should be within the preferred zone of 45 to 75 to the horizontal, or the optional
� �
zone of 30 to 45 to the horizontal, as shown in Figure 5,
5) belts should not be held away from the body by wheelchair components or parts such as the wheelchair
armrests or wheels, along with an illustration similar to that of Figures 7 and 8,
©
10 ISO 2001 – All rights reserved
---------------------- Page: 15 ----------------------
ISO 10542-1:2001(E)
6) occupant restraints belts should be adjusted as firmly as possible consistent with user comfort,
7) upper-torso restraints should fit over the shoulders,
8) upper-torso anchor or webbing guide points that are adjustable in height should be set at or above the
wheelchair occupant's shoulder so as not to impose downward loads on the spine in the event of an impact,
9) restraint webbing should not be worn twisted.
Dimensions in millimetres
Rigid vehicle components that are inside the clear zones should be covered with padding that conforms with the
impact performance requirements of FMVSS 201, EC 74/60 or UN/ECE 21.
NOTE 1 The rear clear zone is measured from the rearmost point on
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.