ISO/PRF 29061-4

ISO/DISPRF 29061-4:2025(en)
ISO/DIS 29061-4
ISO TC 22/SC 36/WG 2
Secretariat: SIS AFNOR
Date: 2025-07-1511-11
Road vehicles — Methods and criteria for usability evaluation of
child restraint systems and their interface with vehicle anchorage
systems — —
Part 4:
Securing of child in child restraint system and daily handling aspects
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 4: Sécuriser l'enfant dans les systèmes de retenue pour enfant, et aspects de manipulation quotidienne
PROOF
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Published in Switzerland
ii
ISO/DISPRF 29061-4:2025(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Usability evaluation procedure and scoring principles . 2
4.1 Evaluation procedure . 2
4.2 Scoring system . 3
5 Usability evaluation forms . 3
Annex A (informative) Recommendations regarding scoring and assessment . 14
Annex B (informative) Example usability rating classes . 15
Bibliography . 16

iii
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
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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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
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represent the latest information, which may be obtained from the patent database available at
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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 22, Road vehicles, Subcommittee SC 36, Safety
and impact testing.
This second edition cancels and replaces the first edition (ISO 29061-4:2017), which has been technically
revised.
The main changes are as follows:
— — reviewed terminology to cover technology and regulation updates since the first edition;
— — editorial review.
A list of all parts in the ISO 29061 series can be found on the ISO website.
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/DISPRF 29061-4:2025(en)
Introduction
The usability of a child restraint system (CRS) in terms of ease of:
— — installation of CRSs in various vehicles; and
— — day-to-day use with a child (e.g. securing, harnessing, adaption for a growing child)
is of utmost importance to ensure that a CRS is used properly in accordance with the manufacturer's
intentions, and to ensure that a correctly installed CRS will provide the best possible protection in a crash
situation. An international agreement on usability criteria and measurements is beneficial for both consumers
and manufacturers.
The aim of this document is to provide a usability evaluation system related to securing of a child in the child
seat and other daily handling aspects, 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 child restraint 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, IIHS) and
the European Union (EU) (NPACS and consumer rating programmes, such as ICRT, ADAC).
v
DRAFT International Standard ISO/DIS 29061-4:2025(en)

Road vehicles — Methods and criteria for usability evaluation of child
restraint systems and their interface with vehicle anchorage systems
— —
Part 4:
Securing of child in child restraint system and daily handling aspects
1 Scope
This document provides criteria for judgement of usability of child restraint systems (CRS) with regard to the
securing of a child in the child seat and other daily handling aspects.
This document provides criteria for judgement of:
— — 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 securing the child or child dummy in a
CRS installed in vehicle.
This document can be used in conjunction with either ISO 29061-1 or ISO 29061-3 for making a complete
usability evaluation of CRSs attached to the vehicle with ISOFIX/LATCH or vehicle seat belts.
NOTE 1 CRS includes enhanced child restraint systems (ECRS) according to UN Regulation No. 129.
NOTE 2 Booster system usability evaluation, including securing of a child in the booster system, is covered by
ISO 29061-5.
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 29061--1, Road vehicles — Methods and criteria for usability evaluation of child restraint systems and their
interface with vehicle anchorage systems — Part 1: Vehicles and child restraint systems equipped with ISOFIX
anchorages and attachments
ISO 29061--3, 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
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology 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 3.1
audible
capable of being heard in normal environmental conditions
3.2 3.2
child restraint system
CRS
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-only restraints, toddler seats (forward and
rearward-facing), booster cushions, and booster seats. Combination products may cover two or more of these product
categories.
3.3 3.3
usability
extent to which a vehicle or child restraint system (CRS) (Error! Reference source not found.(3.2)) is capable
of being used and is convenient and practical in use (separately or combined)
3.4 3.4
slack
looseness of an adjustable strap that is likely to affect the performance of the child restraint system (CRS)
(Error! Reference source not found.(3.2)) adversely
3.5 3.5
harness
child restraint system (CRS) (Error! Reference source not found.(3.2)) belt assembly comprising shoulder
restraints, a crotch strap and optionally lap straps
4 Usability evaluation procedure and scoring principles
4.1 Evaluation procedure
This document provides a procedure to evaluate the usability related to the securing of child in child restraints,
and other daily handling aspects. It shall be used in conjunction with ISO 29061--1 or ISO 29061--3 for a
complete usability evaluation of CRSs attached to the vehicle with ISOFIX/LATCH or vehicle seat belts.
The procedure evaluates ease of availability of instruction, clarity of instruction manual and labelling, and the
ease of use of design-related features of the CRS related to the securing of child in the CRS and daily handling
aspects.
The assessment is done in two steps:
— — a separate assessment of the CRS; and
— — a usability assessment when securing a child or child dummy, with the CRS installed in a vehicle, or in
a simulated vehicle setup.
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 aspects of the process takes about 30 min.
ISO/DISPRF 29061-4:2025(en)
The necessary materials include:
— — the usability evaluation form (in either paper or electronic format);
— — the child restraint instruction manual, including instruction video if applicable;
— — a screwdriver, or a simple prying/turning tool;
— — a force gauge for measuring belt tension.
Initially, the child restraint shall be in the condition as supplied to the consumer. The evaluation process
includes all the steps, including assembly, to complete the installation.
Unpacking the CRS, removing the box and plastic protections, detaching the handbook, etc. shall be
disregarded in the evaluation, but other initial one-time preparations are considered and assessed in the
forms.
The mode of use for the child restraint and the seating position in the vehicle shall be determined in advance
and documented in the evaluation form.
The evaluation process first addresses the labels and instructions, followed by the ease of positioning and
securing the child or the child dummy in the CRS, in a vehicle environment.
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 shall 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 appropriate. The final rating consists of a total number of points that shall be expressed
as a percentage of the maximum possible score for the particular conditions. See also further
recommendations given in Annex AAnnex A. Example of usability rating classes is given in Annex BAnnex B.
5 Usability evaluation forms
The following are the usability evaluation forms:
— — Form 1: separate evaluation of CRS: Rearward facing (RF), forward facing (FF) or lateral/transverse
facing (LF) with internal harness or shield;
— — Form 2: evaluation in a vehicle environment;
To enhance the value and applicability of this document, the forms are also provided in a revisable [MS
1 1)
Excel ] ] format. These forms are provided at the following URL: https://standards.iso.org/iso/29061/-4/ed-
2/en.
MS Excel is an example o
...