UN R127 Supplement 4 (04 series) · UNECE Regulation No. 127 (ECE R127) — Uniform provisions concerning the approval of motor vehicles with regard to their pedestrian safety performance.
UN R127 — Supplement 4 to the 04 series of amendments
Supplement 3 → 4
- What changed
- The Regulation now accounts for vehicles of category X and does not apply to vehicles of category Y.
- For all tests to the windscreen, resultant acceleration and jerk histories must now be provided, evaluated against the atypical fracture criteria and reported for monitoring.
- The upper legform impactor joint friction torque is now set to a minimum of 650 Nm but no more than 850 Nm.
- Why
- The TF-AVRS proposal was prepared to enable the application of the Regulation to vehicles equipped with an Automated Driving System (ADS).
- The windscreen proposal was prepared to clarify the scope of data from tests to the windscreen that must be provided for type approval.
- The expert from Germany proposed to change the torque values of the upper legform impactor to avoid damaging it during tests.
Q1What changed53 changes
Introduction and scope for vehicles of categories X and Y (section 0., paragraphs 1.1. and 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. Without a driver or manual driving controls in the vehicle, related provisions must not be taken into account, unless this amendment already covers them. For vehicles with an ADS other than vehicles of 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. Footnote 1 of sections 0. and 1. now refers to document ECE/TRANS/WP.29/78/Rev.8 instead of Rev.6.
Vehicles of category X, and the ARHSS when an ADS feature is performing the DDT (paragraphs 1.2., 1.3., 2.27., 2.29. and 5.3.1.2.)
For vehicles of category X, paragraphs 1.2. and 1.3. now take the "R" point of the most forward passenger seat instead of the driver's R-point. In the definition of "Mass in running order" (para. 2.27.), a driver’s mass is not included for vehicles of category X. For the "Normal ride attitude" of vehicles of category X, two passenger masses are placed on the front seats instead of the driver's and one passenger masses. Paragraph 5.3.1.2. covers an ARHSS engaged for use in exceptional low speed use cases on public roads. At the end of its second sentence, it adds "or whilst an ADS feature is performing the DDT". A new footnote on the DDT refers to R.E.3, document ECE/TRANS/WP.29/78/Rev.8, para. 1.17, for its definition.
Atypical windscreen fracture behaviour and windscreen test histories (paragraph 2.48., Annex 5, paragraphs 4.1. and 5.1.)
In paragraph 2.48., cases (a) and (b) of atypical windscreen fracture behaviour now refer to the resultant headform acceleration. Case (a) now ends with "and/or" instead of "or". For all tests to the windscreen, Annex 5, paragraphs 4.1. and 5.1., now require resultant acceleration and jerk versus time histories. These histories must be evaluated against the atypical fracture criteria according to paragraph 2.48. and reported for monitoring purposes according to paragraphs 4.8. to 4.10. New Figure 6 shows the evaluation of resultant acceleration and jerk for tests to the windscreen. A new note says that both alternatives, 1 graph for each criterion or 1 graph for both criteria, are accepted.
Sharing of cowl monitoring area and windscreen test results through DETA (paragraphs 4.8. to 4.10.)
Each Contracting Party must, by its Approval Authority, inform other Approval Authorities about the test results of the cowl monitoring area and the windscreen. This information must be shared at the first approval, and with each extension when new tests in these areas have been performed. This information is intended for the collection and analysis of the cowl area and atypical windscreen fracture behaviour, to further develop future amendments. The information referred to in paragraph 4.8. must be uploaded in English to the secure internet database "DETA". The Approval Authority must upload the type approval and these test results to DETA within 14 days after the day of granting (para. 4.10.).
Additional character in the approval mark for the WAD 2,100 boundary (paragraph 4.4.3., Annex 2)
New paragraph 4.4.3. says that the approval mark must contain an additional character after the type approval number. Its purpose is to distinguish vehicles approved based upon the specific provisions related to WAD 2,100 boundary from those with the extended WAD 2,500 boundary. The letter should be chosen according to paragraph 4.2. The Annex 2 example text now says the letter "T" indicates approval using the specific provisions on WAD 2,100 boundary in accordance with paragraph 11.19. The example approval mark is also changed, and the text under the Annex 2 heading now refers to paragraphs 4.4. to 4.4.3. The footnote of paragraph 4.4.1. on the distinguishing numbers of the Contracting Parties now refers to Rev.8 instead of Rev.6.
Paragraphs 11.1. to 11.25. and the WAD 2,100 boundary line of Annex 1, Part 2, paragraph 16.1.
Paragraphs 11.1. to 11.15. are now "(deleted)". Under paragraph 11.19., type approvals using the test proceedings related to atypical windscreen fracture behaviour continue to be granted until 1 September 2033, not 2028. Paragraph 11.24. says that Contracting Parties may grant type approvals according to any preceding series of amendments. Paragraph 11.25. says that Contracting Parties must continue to grant extensions of existing approvals to any preceding series of amendments. In Annex 1, Part 2, paragraph 16.1., the WAD 2,100 boundary line now refers to paragraphs 11.19. to 11.23. instead of 11.9 to 11.11. The coordinate system footnote of paragraph 16.1. now refers to Annex B of Addendum 6 of Mutual Resolution No. 1 (M.R.1), not R.E.3.
Joint friction torque of the upper legform impactor (Annex 4, paragraph 3.5., Annex 6, paragraph 2.4.1.)
In Annex 4, paragraph 3.5., the joint friction torque is now set to a minimum of 650 Nm but no more than 850 Nm. Annex 6, paragraph 2.4.1., on the upper legform impactor certification, now gives the same joint friction torque setting. Before, both paragraphs set the joint friction torque to 675 Nm ± 25 Nm.
Q2Why it changed
- Proposed by
- Experts from Germany and the Kingdom of the Netherlands (windscreen tests); expert from Germany (upper legform impactor); 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 TF-AVRS proposal was prepared to enable the application of the Regulation to vehicles equipped with an Automated Driving System (ADS). The Regulation was originally drafted for vehicles with a driver and manual driving controls. The amendment intends to keep the spirit of the Regulation. It also intends to extend its application to vehicles without a driver and without manual driving controls inside the vehicle.
Sources (4)
“to enable the application of the regulation to vehicles equipped with an Automated Driving System (ADS)”
“See paragraph 0. in the proposal”
“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 without manual driving controls inside the vehicle”
A clarification was needed that the definition of atypical windscreen fracture behaviour refers to the resultant acceleration of all three axes (x, y and z). It is also clarified that all three alternatives are allowed: (a) only, (b) only, or both (a) and (b).
Sources (2)
“A clarification is needed that the resultant acceleration of all three axes (x, y and z) is referred to in this definition”
“Also it is clarified that all three alternatives are allowed”
Annex 5, paragraphs 4.8. and 5.8., of the 03 series require tests with atypical windscreen fracture to be duly recorded in the test report. However, atypical behaviour during windscreen tests that meet the performance criteria may not be detected. So provisions are needed as a guideline of the scope of data that must always be provided during the type approval procedure.
Sources (2)
“Paragraphs 4.8. and 5.8. of annex 5 of the 03 series of amendments to UN Regulation No. 127 prescribe tests with atypical windscreen fracture to be duly recorded in the test report”
“since atypical behaviour during windscreen tests meeting the performance criteria may not be detected, provisions are needed as a guideline of the scope of data that must always be provided during the type approval procedure”
The shared information is intended for the collection and analysis of the cowl area and atypical windscreen fracture behaviour, to further develop future amendments.
Source
“This information is intended to be shared for the purposes of collection and analysis of the cowl area and atypical windscreen fracture behaviour in order to be able to further develop future amendments of the Regulation”
The expert from Germany proposed to change the torque values of the upper legform impactor to avoid damaging it during tests. The 650 Nm minimum is set to avoid damages to the impactor, to further test equipment or to the test stand during severe vehicle impacts. The relatively small corridor with an upper limit of 700 Nm may lead to unnecessary burden during the quasistatic certification. A moderate increase of the maximum setting is associated with no higher risk for damage to the impactor or the guidance system. It may reduce the efforts and costs of the certification significantly, so the upper limit of 850 Nm is recommended.
Sources (6)
“proposals to change the torque values of the upper legform impactor to avoid damaging it during tests”
“For the full justification, please refer to ECE/TRANS/WP.29/GRSP/2025/39”
“To avoid damages to the upper legform impactor, to further test equipment or to the test stand during severe vehicle impacts, the torque limiting joint is set to a minimum of 650 Nm”
“the relatively small corridor for the setting with an upper limit of 700 Nm may lead to unnecessary burden during the quasistatic certification”
“a moderate increase of the maximum torque setting for obtaining a broader certification corridor is associated with no higher risk for damage to the impactor or the guidance system”
“may reduce the efforts and costs of the certification significantly, it is recommended to raise the upper limit to 850 Nm”
Document trail
- 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/29Windscreen test proposal by the experts from Germany and the Kingdom of the Netherlands
- 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/36ADS proposal by the expert from Germany on behalf of TF-AVRS
- 2025-09ProposalECE/TRANS/WP.29/GRSP/2025/40Upper legform impactor proposal by the expert from Germany
- —Amended in sessionGRSP-78-29TF-AVRS changes to ECE/TRANS/WP.29/GRSP/2025/36
- —Working party adoptsECE/TRANS/WP.29/GRSP/78GRSP session report, paras. 28, 30 and 43 and Annex XVII
- 2026-03Sent to WP.29ECE/TRANS/WP.29/2026/53Text that GRSP sent to WP.29 and AC.1
- —Amended in sessionWP.29-199-10Amendments for the AC.1 vote, reproduced in Annex VI of ECE/TRANS/WP.29/1192
- 2026-06-24WP.29 adoptsECE/TRANS/WP.29/1192Adopted at the 199th session (session report, para. 103)
- PendingIn forceDate not yet known
Q3Who is affected
Vehicle manufacturer
- Check if your vehicles are of category X or of category Y; this Regulation does not apply to category Y.
- For vehicles of category X, use the "R" point of the most forward passenger seat in paragraphs 1.2. and 1.3.
- For approvals using the test proceedings related to atypical windscreen fracture behaviour, check the new date in paragraph 11.19.
Component supplier
- No direct action for this role.
Technical service / Approval authority
- If the vehicle has no driver or manual driving controls, ignore related provisions unless this amendment already covers them.
- For the normal ride attitude of vehicles of category X, make sure two passenger masses are on the front seats.
- For all tests to the windscreen, make sure resultant acceleration and jerk histories are evaluated against the paragraph 2.48. criteria.
- Set the upper legform impactor joint friction torque to a minimum of 650 Nm but no more than 850 Nm.
- As Approval Authority, share cowl monitoring area and windscreen test results at first approval and at extensions with new tests.
- As Approval Authority, upload the type approval and these test results to DETA in English within 14 days after granting.
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ⓘ This report gives advice only. It is not legal or type-approval advice.