Road vehicles — Methods and criteria for usability evaluation of child restraint systems and their interface with vehicle anchorage systems — Part 3: Installation of child restraint systems using vehicle seat belts
ISO 29061-3:2017 specifies the criteria for judgement of usability of child restraint systems (CRS) when installing them with the vehicle seat belts. ISO 29061-3:2017 provides criteria for judgement of: - ease of availability of instructions; - clarity of instruction manual and labelling; and - ease of use of design related features of the CRS related to the installation in a vehicle. NOTE Booster system usability evaluation is covered by ISO 29061-5.
Véhicules routiers — Méthodes et critères pour l'évaluation de la facilité d'utilisation des systèmes de retenue enfants et leurs interfaces avec les systèmes d'ancrage dans le véhicule — Partie 3: Installation des systèmes de retenue pour enfant utilisant les ceintures de sécurité
Standards Content (Sample)
Road vehicles — Methods and criteria
for usability evaluation of child
restraint systems and their interface
with vehicle anchorage systems —
Installation of child restraint systems
using vehicle seat belts
Véhicules routiers — Méthodes et critères pour l'évaluation de la
facilité d'utilisation des systèmes de retenue enfants et leurs interfaces
avec les systèmes d'ancrage dans le véhicule —
Partie 3: Installation des systèmes de retenue pour enfant utilisant les
ceintures de sécurité
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1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Usability evaluation procedure and scoring principles . 3
4.1 Evaluation procedure . 3
4.2 Scoring system . 4
5 Usability evaluation forms . 4
Annex A (informative) Recommendations regarding scoring and assessment .17
Annex B (informative) Example usability rating classes .18
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bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 36,
Safety and impact testing.
A list of all parts in the ISO 29061 series can be found on the ISO website.
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The usability of a child restraint system (CRS) in terms of ease of:
— installation of child restraint systems in various vehicles; and
— day-to-day use with a child (e.g. securing, harnessing, adaption for a growing child, etc.)
is of utmost importance to ensure that a child restraint system is used properly in accordance with the
manufacturer's intentions, and to ensure that it will provide maximum protection in a crash situation.
An international agreement on usability criteria and measurements is beneficial for both consumers
The aim of this document is to develop and validate a usability evaluation system for installation of
child restraint systems with vehicle seat belts to promote improved design for an easy and correct use.
It provides child restraint and vehicle manufacturers with a tool for the assessment of the usability
of new and current systems. At the same time, it provides consumers (parents and caregivers) with
usability information on the key features related to the proper use of the attachment system, and assist
them in selecting child restraints and vehicles that are easy to use properly.
The ISO usability evaluation system has been developed with participation from, and considering the
experiences from, usability rating systems of Canada (Transport Canada and ICBC), USA (NHTSA), EU
(NPACS and consumer rating programmes, such as ICRT, ADAC).
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INTERNATIONAL STANDARD ISO 29061-3:2017(E)
Road vehicles — Methods and criteria for usability
evaluation of child restraint systems and their interface
with vehicle anchorage systems —
Installation of child restraint systems using vehicle seat
This document specifies the criteria for judgement of usability of child restraint systems (CRS) when
installing them with the vehicle seat belts.
This document provides criteria for judgement of:
— ease of availability of instructions;
— clarity of instruction manual and labelling; and
— ease of use of design related features of the CRS related to the installation in a vehicle.
NOTE Booster system usability evaluation is covered by ISO 29061-5.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
capability of being heard in normal environmental conditions
child restraint system
free-standing device intended to provide child vehicle occupants with an approved restraint
Note 1 to entry: CRSs comprise various categories such as car beds, infant restraints, toddler seats (forward and
rearward-facing), booster cushions, and booster seats. Combination products may cover two or more of these
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multiple modes CRS
type of CRS (3.2) that can be used in several modes, for example converting from integral to non-integral
or for use in different orientations
any deviation from the intended application and use of a CRS (3.2) that might reduce its protective
illustration or photo used to represent a concept or an operation which can be supplemented by text
type of anti-rotational device intended to restrict the rearward rotation of a rearward-facing CRS (3.2)
Note 1 to entry: It usually comprises a rigid device that, when in its operational position, rests against the car
type of anti-rotational device intended to restrict the rearward rotation of a rearward-facing CRS (3.2)
Note 1 to entry: It usually comprises a tether strap or other hardware attached near the back or base of the CRS
that connects to a rebound tether (lower tether) anchorage. It incorporates a device to enable it to be connected
to such an anchorage.
rebound tether anchorage
lower tether anchorage
anchorage on the vehicle seat track or on or close to the vehicle floor to which a rebound tether (3.6)
(lower tether) can be attached
operation that can be completed without the need to undertake a secondary action
EXAMPLE This includes tightening a strap by pulling it without the need to release a locking system; or
attaching to an anchorage without the need to depress the seat cushion.
unintended looseness of a strap that is likely to affect adversely the performance of the CRS (3.2)
type of anti-rotational device comprising a permanent attachment to a child restraint system (3.2), or
a base of a child restraint system, creating a compressive load path between the child restraint and
a vehicle structure (for example the vehicle floor) to prevent or reduce forward rotation of the child
Note 1 to entry: A support leg may be adjustable.
tether strap attached at or near the top of a CRS (3.2), incorporating a device to enable it to be connected
to a top tether anchorage (3.11.1)
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top tether anchorage
device, such as a ring, bar, bracket, or webbing loop, and its underlying structure, either user-ready or
aftermarket-installed, to which a top tether (3.11) can be attached
top tether strap
webbing strap which extends from the top of a CRS (3.2) to the top tether anchorage (3.11.1) and which
is equipped with an adjustment device, a tension-relieving device and a top tether (3.11) connector
extent to which a product can be used by specified users to achieve specified goals with effectiveness,
efficiency and satisfaction in a specified context of use
Note 1 to entry: Interpretation of the generic definition for the purpose of this document: the extent to which
a CRS (3.2) is capable of being used and is convenient and practical in use (separately or in combination with a
[SOURCE: ISO 9241-11:1998, 3.1, modified — a new Note 1 to entry has been added.]
4 Usability evaluation procedure and scoring principles
4.1 Evaluation procedure
This document provides a procedure to evaluate the usability of child restraint systems, equipped
with integral harness or shield, intended to be installed in the vehicle using the vehicle seat belts. The
procedure evaluates ease of availability of instructions, clarity of instruction manual and labelling, and
the ease of use of design-related features of the CRS related to the installation in a vehicle.
The assessment is done in two steps:
— a separate assessment of the child restraint system; and
— a usability assessment when installing the child restraint system in specified vehicle seating
The evaluation takes into consideration the various modes of installation and conversions between
installation modes. The usability protocol is intended to be objective and repeatable.
The evaluation is most easily accomplished using a team of two people having basic knowledge of
child restraints and being familiar with the technical terms used. However, they should preferably be
unfamiliar with the CRS model to be evaluated.
The procedure for all three aspects of the process, the child restraint, the vehicle seating position, and
the resulting interface, takes about 45 min.
The materials necessary include:
— the usability evaluation form (in either paper or electronic format);
— the vehicle owner’s manual;
— the child restraint manual, including instruction video if applicable; and
— a screwdriver, or a simple prying/turning tool.
A copy of the terms and definitions from this document may also be helpful.
Initially, the child restraint should be in the condition as supplied to the consumer. The evaluation
process includes all the steps, including assembly, to complete the installation.
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Unpacking the CRS, removing the box and plastic protections, detaching the handbook, etc., should be
disregarded in the evaluation, but other initial one-time preparations are considered and assessed in
The mode of use for the child restraint (i.e. forward-facing/rearward-facing, upright/reclined, with
base/without base) and the seating position in the vehicle should be determined in advance and
documented in the evaluation form.
The evaluation process first addresses the labels and instructions, followed by the ease of installation
and removal of the child restraint system.
4.2 Scoring system
The scoring system consists of a Good/Average/Poor rating (scored with 3/1/0 points) of each
item assessed, and an importance rating A/B/C (scored with 3/2/1 points) for each item. For each
assessment, the scoring of the above are multiplied. A maximum score for a "Good" solution on an item
with "A" importance is 9 points.
In this document, “average” means “mid-level” and should not be perceived as a statistical average
between good and poor.
The maximum possible score will depend on the features and usage of the restraint and vehicle.
Different products may have different maximum possible scores, and therefore, comparisons of the raw
number of total points would not be meaningful. The final rating consists of a total number of points
that should be expressed as a percentage of the maximum possible score for the particular conditions.
See also further recommendations given in Annex A.
5 Usability evaluation forms
See the following pages.
To enhance the value and applicability of this document, the forms are also provided in a revisable
[MS Excel ] format. These forms are provided at the following URL: http://standards.iso.
1) MS Excel is an example of a suitable product available commercially. This information is given for the convenience
of users of this document and does not constitute an endorsement by ISO of this product.
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Date of evaluation Evaluated by Test no.
Form 1: Separate evaluation of CRS: Rearward facing (RF), forward facing (FF) or lateral facing (LF) with internal harness or shield
Child restraint system evaluated Infant only CRS, RF Infant only CRS, LF RF only toddler CRS FF only CRS
Manufacturer Multiple modes CRS (2-in-1) Multiple modes CRS (3-in-1)
Child seat make and model Base make and model (if applicable)
Country/Region of use Country/Region of use
Approval no. (where applicable) Approval no. (where applicable)
Production no. Production no.
Date of manufacturing, yyyy-mm-dd Date of manufacturing, yyyy-mm-dd
Type (E.g. UN-ECE Group 0+/I/II) Primary anti-rotational device Top tether Support leg N/A
Rebound tether Rebound bar
CRS has separate base Yes No Secondary anti-rotational device N/A
Appropriate child size range for this
mode according to manual Mass range (kg): Height range (cm): Age range (months or years):
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Form 1.1: CRS instructions and labels
Good Average Poor Importance N/A Notes
Do CRS or base instructions Illustrated clearly with Pictures plus written Meth