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UN R17 Supplement 1 (12 series) · UNECE Regulation No. 17 (ECE R17) — Uniform provisions concerning the approval of vehicles with regard to the seats, their anchorages and any head restraints.

UN R17 — Supplement 1 to the 12 series of amendments

Base text → Supplement 1

Adopted at the WP.29 199th sessionEntry into force not yet known
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What changed
  • The Regulation now accounts for vehicles of category X and does not apply to vehicles of category Y.
  • In the definition of “Head restraint”, the words “at any point” are now “at at least one point”.
  • Several head restraint provisions now use the longitudinal vertical plane passing through the R-point instead of the torso line or the reference line.
Why
  • The amendment intends to keep the spirit of the Regulation and to extend its application to vehicles without a driver and manual driving controls.
  • The expert from CLEPA proposed to align the definition of “Head restraint” with a principle understood during the creation of UN Global Technical Regulation No. 7.
  • The proposals also aim to harmonize the set-ups of all tests and to correct and clarify the text of the Regulation.

Q1What changed38 changes

Introduction and scope for vehicles of categories X and Y (section 0., paras. 1.1. to 1.4.)

New section 0. says that the Regulation is amended to account for vehicles of category X. New paragraph 1.4. says that the Regulation does not apply to vehicles of category Y. The three existing paragraphs of section 1. are now numbered 1.1. to 1.3. Without a driver or manual driving controls, provisions related to them must not be taken into account, unless this amendment already covers them. For vehicles with an ADS other than category X, no special provisions or exemptions apply in the manual driving mode. In a mode where an ADS feature is active, the relevant ADS requirements apply.

Introduction
For supplement 1 to the 12 series of amendments:
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Definition of “Head restraint” and the plane through the R-point (paras. 2.13., 5.5.1.2. and 5.6.3., Annexes 4 and 12)

In the definition of “Head restraint” (para. 2.13.), the words “at any point” are now “at at least one point”. The two planes are now 85 mm on either side of the longitudinal vertical plane passing through the R-point, not of the torso line. Paragraph 5.6.3. and Annex 4, paragraph 2.4., now use the longitudinal vertical plane passing through the R-point for the distances L and L'. At the end of paragraph 5.5.1.2., “reference line” is now “longitudinal vertical plane passing through the R-point”. Annex 4 has a new Figure 4-1, and its labels include the longitudinal vertical plane passing through the R-point. In Annex 12, paragraph 3.3.2., the lateral distance of 70 mm is now from the “longitudinal vertical plane passing through the R-point centreline”.

"Head restraint" means at any designated seating position, a device that limits rearward displacement of a seated occupant's head relative to the occupant's torso and that has a height equal to or greater than 700 mm at any at least one point between two vertical longitudinal planes passing at 85 mm on either side of the torso linelongitudinal vertical plane passing through the R-point, in any position of backset and height adjustment, as measured in accordance with Annex 10.
When measured in accordance with Annex 4, the lateral width of a head restraint shall be not less than 85 mm on either side of the torso line longitudinal vertical plane passing through the R-point (distances L and L').
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Gap measurement in Annex 8 (para. 2.3. and notes under Figures 8-1 and 8-2)

In Annex 8, paragraph 2.3. now says that the area of measurement is on the front face of the head restraint. The two planes are now 85 mm on either side of the longitudinal vertical plane passing through the R-point, not of the torso line. The notes under Figures 8-1 and 8-2 no longer say “without exerting any load”.

The area of measurement is on the front face of the head restraint, anywhere between two vertical longitudinal planes passing at 85 mm on either side of the torso line longitudinal vertical plane passing through the R-point and above the top of the seat back at a height greater than 540 mm.
Section A-A is to be made in a point of the gap area which allows the maximum sphere intrusion, without exerting any load.
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Energy dissipation test of the head restraint rear face (para. 5.5.2., Annex 6)

Paragraph 5.5.2. now names the energy dissipation test, not the energy absorption test, for parts of rear faces of head restraints in area 1. In Annex 6, paragraph 1.4.2.1. now gives the direction of impact for the rear face. The impact is from the rear towards the front, in a longitudinal plane at an angle of 45° from the vertical. Before, this paragraph gave a horizontal direction of impact from the front towards the rear, for the front face. Paragraph 1.4.2.2. now covers only the rear zones and refers to figure 10-4 instead of paragraph 6.5.

Parts of the rear faces of the head restraints situated in area 1, as defined in paragraph 6.8.1.1.3. below shall pass the energy absorption dissipation test.
For the front rear face, the direction of impact from the front rear towards the rear front shall be horizontal in a longitudinal plane at an angle of 45° from the vertical.
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Test headings, references and the word “driver” (paras. 5.2.2., 6.4. and 6.4.3., Annexes 14 and 15)

Paragraph 6.4. now has the heading “Displacement and strength test of head restraint”. Paragraph 6.4.3. now says that Annex 5 describes the test for rearward displacement and for strength of the head restraint and its anchorages. Paragraph 5.2.2. now refers to paragraph 2.8. instead of 2.7., and Annex 15, paragraph 5.1., refers to paragraph 5.6.2. instead of 5.6.1. In Annex 14, paragraph 3.1.7.8. now says “the dummy” instead of “the driver dummy”. In Annex 15, paragraph 1. now reads “except a driver’s designated seating position” instead of “except the driver’s designated seating position”.

Test of the performance of the head restraintDisplacement and strength test of head restraint
Test for determining rearward displacement for the head restraint and strength of head restraint and its anchorages is described in Annex 5 to this regulation.
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Backset measurement in Annex 11 (paras. 2. to 2.5.)

In Annex 11, the text of paragraph 2. no longer has the words “and for its dimensions is based on Figure 10-2 of Annex 10”. It now says that the H-Point machine itself is not placed on the seat during this measurement. Paragraph 2.1. now also requires the seat back to be adjusted to its design angle, and old paragraph 2.2. with this step is deleted. Paragraphs 2.3. to 2.6. are renumbered as 2.2. to 2.5. Paragraph 2.5. now also says that all measurements must be taken in the longitudinal vertical plane passing through the R-point.

Procedure for backset measurement using R-point as the reference pointDemonstrate compliance with paragraph 5.6.6. by measuring the R-point backset of the head restraint based on the usage of an apparatus that facilitates the measurement of coordinates. The H-Point machine itself is not placed on the seat during this measurement.
Demonstrate compliance with paragraph 5.6.6. by measuring the R-point backset of the head restraint based on the usage of apparatus that facilitates the measurement of coordinates and for its dimensions is based on Figure 10-2 of Annex 10.
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New R.E.3 references in footnotes 1 and 2

Footnote 1 of sections 0. and 1. now refers to the definitions in R.E.3, document ECE/TRANS/WP.29/78/Rev.8. Footnote 2 of paragraph 4.4.1. now refers to R.E.3 document ECE/TRANS/WP.29/78/Rev.8 for the distinguishing numbers of the Contracting Parties. Before, both footnotes referred to Rev.7. Footnote 1 also no longer has the words “, para. 2” after the document number. In item (b) of section 1., the call to footnote 1 after “M3” is removed.

As defined in the Consolidated Resolution on the Construction of Vehicles (R.E.3.), document ECE/TRANS/WP.29/78/Rev.7, para. 2 ECE/TRANS/WP.29/78/Rev.8 - https://unece.org/transport/vehicle-regulations/wp29/resolutions
The distinguishing numbers of the Contracting Parties to the 1958 Agreement are reproduced in Annex 3 to the Consolidated Resolution on the Construction of Vehicles (R.E.3), document ECE/TRANS/WP.29/78/Rev.7ECE/TRANS/WP.29/78/Rev.8, Annex 3 - https://unece.org/transport/vehicle-regulations/wp29/resolutions
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Q2Why it changed

Proposed by
Experts from France and CLEPA, and the expert from Germany on behalf of the GRSP Task Force on Automated Vehicles Regulation Screening (TF-AVRS)
Working party
GRSP, 78th session (December 2025)

Reasons

  • The Regulation was first written for vehicles with a driver and manual driving controls. The amendment intends to keep the spirit of the Regulation and to extend its application to vehicles without a driver and manual driving controls. The TF-AVRS proposal was prepared to enable the application of the Regulation to vehicles equipped with an Automated Driving System (ADS).

    Sources (4)
    “The Regulation was originally drafted for vehicles with driver and manual driving controls”
    “it is the intention of this amendment to keep the spirit of the regulation and to extend its application to vehicles without driver and manual driving controls”
    “to enable the application of the regulation to vehicles equipped with an Automated Driving System (ADS)”
    “See paragraph 0. in the proposal”

  • During the creation of UN Global Technical Regulation No. 7, it was understood how to decide if a head restraint is present. Under this principle, if seat trim is present “at a height over 700 mm at at least one point within +/- 85 mm from a longitudinal median plane of the seat”, a head restraint is considered present. The definition of head restraint and the word “any” gave another meaning than intended. So the expert from CLEPA proposed to align the definition with this principle.

    Sources (3)
    “During the creation of UN Global Technical Regulation No. 7 it was understood that the following principle shall be applied to decide if a head restraint is present or not in the vehicle”
    “in the case that seat trim is present at a height over 700 mm at at least one point within +/- 85 mm from a longitudinal median plane of the seat”
    “The definition of head restraint and the wording ‘any’ gave another meaning than intended and it is therefore proposed to align to the principle explained”

  • Since the 10 series, some test procedures were referenced to the torso line, but most to the “median longitudinal plane of the seat” or the reference line. To harmonize the set-ups of all tests, the expert from CLEPA proposed to replace the words “torso line” in test procedures.

    Sources (2)
    “Since the 10 series of amendments, some test procedures are referenced to the torso line whereas the majority is referenced to the median longitudinal plane of the seat or to the reference line”
    “In order to harmonize the set ups of all tests we propose to substitute the wording torso line in test procedures”

  • Since the 10 series, the test for energy dissipation on the head restraint is split between Annex 6 (rear part) and Annex 12 (front). But Annex 6 was not correctly updated, and references to the front part of the head restraint remained. When the 10 series moved the displacement and strength test from paragraph 6.4.3. to Annex 5, paragraph 6.4.3. no longer referred to Annex 5. Also, the 09 series asked to measure the gap from the front face of the head restraint, but this wording disappeared in the 10 series. The proposal aims to correct Annex 6 and paragraph 6.4.3., and to put the front face wording back.

    Sources (4)
    “Since the 10 series of amendments, the test procedure for checking energy dissipation on the head restraint has been split between Annex 6 and Annex 12”
    “However, Annex 6 was not correctly updated and references to the front part of the head restraint remain”
    “the test procedure for “Displacement and strength” was transferred from paragraph 6.4.3. to Annex 5 of the regulation, but Annex 5 is not referred anymore on paragraph 6.4.3.”
    “But this wording has disappeared between the 09 and 10 series of amendments to this regulation”

  • In Annex 8, Figures 8-1 and 8-2 asked to measure without exerting any load, but paragraph 2.4. asks for “Applying a load of no more than 5 N against the area of measurement”. In Annex 11, the seat back was adjusted to its design angle after the actual torso angle was evaluated. The proposal aims to correct these two inconsistencies. In Annex 11, the words “and for its dimensions is based on Figure 10-2 of Annex 10” were also not clear, because Figure 10-2 corresponds to effective height. The heading “Test of the performance of the head restraint” of paragraph 6.4. could also mislead, because the term “performance” is used in several other contexts.

    Sources (4)
    “Figure 8-1 and Figure 8-2 requests to make the measure without exerting any load, whereas paragraph 2.4 requests “Applying a load of no more than 5 N against the area of measurement”, which leads to an inconsistency”
    “Annex 11 requests to adjust the seat back to its design angle, after evaluating the actual torso angle”
    “which is not clear concerning the dimensions, because figure 10-2 corresponds to effective height”
    “the title of paragraph 6.4. (Test of the performance of the head restraint) can be misleading, because the term “performance” is used in several other contexts”

Document trail

  1. 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/16Proposal by the expert from Germany on behalf of TF-AVRS
  2. 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/27Proposal by the expert from France
  3. 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/44Proposal by the expert from CLEPA
  4. —Amended in sessionGRSP-78-13-Rev.1France and CLEPA changes to ECE/TRANS/WP.29/GRSP/2025/27 and ECE/TRANS/WP.29/GRSP/2025/44
  5. —Amended in sessionGRSP-78-42TF-AVRS changes to ECE/TRANS/WP.29/GRSP/2025/16
  6. —Working party adoptsECE/TRANS/WP.29/GRSP/78GRSP session report, paras. 19 and 43 and Annex IV
  7. 2026-03Sent to WP.29ECE/TRANS/WP.29/2026/48Text that GRSP sent to WP.29 and AC.1
  8. —Amended in sessionWP.29-199-10Editorial changes, reproduced in Annex VI to the WP.29 session report
  9. 2026-06-24WP.29 adoptsECE/TRANS/WP.29/1192Adopted at the 199th session (session report, para. 103)
  10. PendingIn forceDate not yet known

Q3Who is affected

Vehicle manufacturer

  • Check in R.E.3 (ECE/TRANS/WP.29/78/Rev.8) if your vehicles are of category X or category Y.
  • Check your seat designs against the amended definition of “Head restraint” in paragraph 2.13.
  • Measure the minimum width of your head restraints (Annex 4) from the longitudinal vertical plane passing through the R-point.

Component supplier

  • Give the vehicle manufacturer head restraint widths measured from the longitudinal vertical plane passing through the R-point.
  • Use the name “energy dissipation test” for the paragraph 5.5.2. test in your documents.

Technical service / Approval authority

  • In Annex 4, paragraph 2.4., measure the distances L and L' from the longitudinal vertical plane passing through the R-point.
  • In Annex 8, take the area of measurement on the front face of the head restraint (paragraph 2.3.).
  • Update your Annex 8 gap measurement instructions: the figure notes no longer say “without exerting any load”.
  • Update your Annex 6 rear face test to the impact direction in paragraph 1.4.2.1.
  • In Annex 11, adjust the seat back to its design angle as part of paragraph 2.1.
  • As Annex 11, paragraph 2.5. now says, take all measurements in the longitudinal vertical plane passing through the R-point.
  • In Annex 12, measure the 70 mm lateral distance from the plane given in paragraph 3.3.2.

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ⓘ This report gives advice only. It is not legal or type-approval advice.

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