The IWG RD-ASEP Subgroup on UN R138 and UN R51 held 13 meetings between October 2024 and September 2025 to amend both regulations regarding sound emissions of electric vehicles. On UN R51, the group agreed to introduce electric vehicles into Annex 7 (ASEP) scope and to add optional sounds and SPL limit lines for M₁ and N₁ vehicles based on vehicle speed, using OICA proposal GRBP/2025/29 as basis. On UN R138, the group aimed to clarify existing text, remove grey zones, and ensure adequate safety levels while limiting environmental impact through maximum SPLs. Working documents are planned for submission to GRBP in February 2026.

By this proposal all types of electric vehicles (xEVs) are included in the provisions of ASEP (Annex 7) in UN Regulation No. 51. If applicable, input of the dedicated subgroup of IWG RD-ASEP has been incorporated.

Proposed amendments to the initial proposal

Proposal to amend ECE/TRANS/WP.29/GRBP/2025/27

Proposal to enable the application of the Regulation to vehicles equipped with automated driving systems (ADS).

Proposal to enable application of the Regulation to vehicles equipped with Automated Driving Systems (ADS).

Proposal to replace references to GTR 21 by references to UN R177.

Proposal to introduce a “default mode”, to specify requirements to be applied to the emission of Enhanced Exterior Sound (EES), with the corresponding transitional provisions, and to draw a limit curve to introduce electric vehicles and hybrid electric vehicles that can be propelled without an internal combustion engine operating in the scope of ASEP (Annex 7).

Proposal to update references to the latest version of standard ISO 362-3 (Indoor testing).

Proposal to address electric vehicle enhanced sound issues in the short term until the new 04 series of amendments enters into force.

Proposal to update references the latest international standard specifications ASTM
F2872-25, F2871-25 and F3678-25.

The proposal to avoid certifying bicycle tyres as moped tyres.

Proposal to clarify how to mark the tyre in the case of implement tyres of speed category symbol D and E for mixed applications where the load index shall be the same for free rolling and drive wheel application.

Proposal to

1. delete para. 2.48. concerning material supplier,
2. amend para. 2.51. by referring to the material supplier only and cancel the reference to the material manufacturer,
3. simplify the list of tyres classified as tyre for use in severe snow conditions to be submitted at the application for approval, and
4. clarity and correct certain paragraphs

Proposal to:

1. Clarify that the “supplier of the tread used for the retreading process” is responsible for conformity of production of the
   supplied tread,
2. Align the classification “traction tyre” with UN R117
3. Provide transitional provisions to manage the switch from the requirements given in paragraph 6.2.1. to the ones given in the paragraph 6.2.2.,
4. Correct the omission of provisions for “professional off-road tyre” and their alignment with UN R30,/li>
5. Correct a reference to “Appendix 1” of the 1958 Agreement to “Schedule 1”, and
6. Manage the transition to the new standard reference test tyres (SRTTs)
   19.5 and 22.5 siped