GAR | GRBP-82-35

GRBP-82-35

IWG RD-ASEP Subgroup on UN Regulations Nos. 51 and 138): Status report

Source(s)

Date

2 Sep 2025

Status

Subject

Meeting(s)

GRBP | Session 82 | 3-5 Sep 2025

Agenda item 3. UN Regulation No. 51 (Noise of M and N Categories of Vehicles)

Agenda item 4. UN Regulation No. 138 (Quiet Road Transport Vehicles)

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.

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UNECE server

Related documents

Excerpts from session reports

GRBP | Session 82 | 3-5 Sep 2025

6. Against this background, the expert from OICA presented in detail their proposal that includes EVs in the scope of ASEP provisions in Annex 7 to UN Regulation No. 51, together with supporting data (ECE/TRANS/WP.29/GRBP/2025/29, GRBP-82-06, GRBP-82-08, GRBP-82-09, GRBP-82-38). The experts of several Contracting Parties considered the OICA proposal as an excellent basis, but pointed out that they would need more time to study it and suggested to postpone taking a decision until the next session of GRBP in February 2026.

5. The IWG RD-ASEP Subgroup on UN Regulations Nos. 51 and 138 reported on their activities with the aim to find a satisfactory solution for the sound emissions of electric vehicles (EVs) and to update both UN Regulations (GRBP-82-35). In particular, the Subgroup agreed on the introduction of EVs in the scope of Annex 7 (ASEP) and on the urgency to do so, since some EVs were already equipped with external sound enhancement systems. The Subgroup decided to use the OICA proposal (ECE/TRANS/WP.29/GRBP/2025/29) for further consideration and discussed two main points on UN Regulation No. 51: addition of optional sounds and sound pressure limits for EVs of categories M₁ and N₁.

10. GRBP recalled the status report of the IWG RD-ASEP Subgroup on UN Regulations Nos. 51 and 138 (GRBP-82-35) and the ensuing discussion (paragraphs 5-7 above).