UN R173 Supplement 1 (01 series) · UNECE Regulation No. 173 (ECE R173) — Uniform provisions concerning the approval of the Installation of safety-belts, restraint systems, child restraint systems, ISOFIX child restraint systems and i-Size child restraint systems.
UN R173 — Supplement 1 to the 01 series of amendments
Base text → Supplement 1
- What changed
- In the keys of Annex 6, appendix 2, paragraphs 4.1. to 4.6., item 2 now reads “Dashed line marks area where a support leg is allowed to protrude”.
- The connector area items in the keys of paragraphs 4.1. to 4.8. now refer to UN Regulation No. 44/UN Regulation No. 129.
- Paragraph 4.7. now has the heading “Rearward-facing toddler child restraint system envelope”.
- Why
- The words “specific vehicle” are removed because the type of child restraint is defined in the respective regulation.
- UN Regulation No. 129 also gives the details of the ISOFIX anchors.
- The proposal removes incorrect wording in paragraph 4.7.
Q1What changed29 changes
Figure 1 of Annex 6, appendix 1 (specifications of the fixture)
Annex 6, appendix 1, Figures 1 to 3 are amended, and two drawings are replaced. The weight note now reads “Weight: 23 kg, evenly distributed”. Before, it read “Weight 23kg evenly distributed”. The text “Detail W to Figure 1” is deleted.
Support leg area in the keys of Annex 6, appendix 2, paragraphs 4.1. to 4.6.
In the keys of paragraphs 4.1. to 4.6., item 2 now reads “Dashed line marks area where a support leg is allowed to protrude”. The words “or similar” and “of a specific vehicle CRS” are removed.
Connector area references in the keys of paragraphs 4.1. to 4.6.
In the keys of paragraphs 4.1. to 4.6., item 4 now refers to UN Regulation No. 44/UN Regulation No. 129 for the connector area. Before, it named UN Regulation No. 44.
Paragraph 4.7.: heading, Figure 7 caption, dimension note and key item 4
Paragraph 4.7. now has the heading “Rearward-facing toddler child restraint system envelope”. Before, the heading was “Lateral facing child restraint systems envelope”. The caption of Figure 7 now reads “ISO/R2X Envelope dimensions of a Reduced-Size Rearward Facing toddler CRS, modified for improved compatibility with the vehicle interior”. The note below the figure now reads “(all dimensions in mm)” instead of “(all dimensions in millimeters)”. Key item 4 now refers to UN Regulation No. 44/UN Regulation No. 129 for further specifications of the connector area. Before, it referred to detail Y and ISO 13216-1:1999, Figures 2 and 3.
New paragraphs 4.8. to 4.10., key of paragraph 4.8. and dimension notes
New paragraphs 4.8., 4.9. and 4.10. have the headings “Lateral facing child restraint systems envelope”, “i-Size support leg” and “i-Size support leg installation assessment volume”. In the key of paragraph 4.8., new item 3 refers to UN Regulation No. 44/UN Regulation No. 129 for further specifications of the connector area. The notes below the figures of paragraphs 4.8. and 4.10. now read “(all dimensions in mm)” instead of “(all dimensions in millimetres)”. Paragraph 4.9. now has the note “(all dimensions in mm)” below its figure.
Q2Why it changed
- Proposed by
- Expert from the Kingdom of the Netherlands, on behalf of the members of the Technical Services Group
- Working party
- GRSP, 77th session (May 2025)
Reasons
The text was presented to update captions under ISO envelope drawings in appendix 2 to annex 6, including adding references to UN Regulation No. 129.
Source
“to update the captions underneath multiple International Organization for Standardization (ISO) envelope drawings in appendix 2 to annex 6, including adding references to UN Regulation No. 129”
The words “specific vehicle” are removed because the type of child restraint is defined in the respective regulation. The proposal says that a conflict exists with the old wording.
Sources (2)
“Removal of the wording “specific vehicle” since the type of child restraint is defined in the respective regulation.”
“With the present wording a conflict exists.”
A reference to UN Regulation No. 129 is added because the details of the ISOFIX anchors are also given in UN Regulation No. 129.
Source
“Addition of a reference to UN Regulation No. 129 since the details of the ISOFIX anchors are also given in UN Regulation No. 129.”
The proposal removes incorrect wording in paragraph 4.7.
Source
“Removal of incorrect wording in paragraph 4.7.”
Proposer's reason (informal document GRSP-77-55)
Figure 1 in Annex 6, Appendix 1, was originally introduced as Figure 1 in Annex 17, Appendix 1 of UN Regulation No. 16. An error in Figure 1 of the consolidated revision 10 of UN Regulation No. 16 was copied into UN Regulation No. 173. The original figures are included again to correct this.
Submitted by Kingdom of the Netherlands. Working party adoption: ECE/TRANS/WP.29/GRSP/77, para. 34.
Sources (4)
“Figure 1 in Annex 6, Appendix 1, was originally introduced as Figure 1 in Annex 17, Appendix 1 of UN Regulation No. 16”
“In the consolidated revision 10 of UN Regulation No. 16, an error was introduced in Figure 1”
“This error then persistently remained and got copied into the new UN Regulation No. 173.”
“By including the original figures again, this has now been corrected.”
Document trail
- —ProposalGRSP-76-17Proposal by the expert from the Netherlands on which ECE/TRANS/WP.29/GRSP/2025/5 is based
- 2025-02RevisedECE/TRANS/WP.29/GRSP/2025/5Proposal by the expert from the Kingdom of the Netherlands, based on GRSP-76-17
- —Amended in sessionGRSP-77-55Modifications to ECE/TRANS/WP.29/GRSP/2025/5
- —Working party adoptsECE/TRANS/WP.29/GRSP/77GRSP session report, para. 34 and Annex VII
- 2025-08Sent to WP.29ECE/TRANS/WP.29/2025/134Text that GRSP sent to WP.29 and AC.1
- 2025-11WP.29 adoptsECE/TRANS/WP.29/1188Adopted at the 197th session (session report, para. 110)
- 2026-06-04In forceC.N.240.2026.TREATIES-XI.B.16.173UN depositary notification
Q3Who is affected
Vehicle manufacturer
- No direct action for this role.
Component supplier
- No direct action for this role.
Technical service / Approval authority
- No direct action for this role.
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ⓘ This report gives advice only. It is not legal or type-approval advice.