Proposal to amend paragraph 2.18. to update Standard Reference Test Tyre definitions to ASTM International standards: E1136-19 for SRTT14, F2493-24 for SRTT16, F2872-25 for SRTT16C, F2871-25 for SRTT19.5, F2870-23 for SRTT22.5, F3678-25 for SRTT19.5 siped, and F3677-23 for SRTT22.5 siped. Also amend paragraph 12.21. to accept existing type approvals and grant extensions to class C₃ tyres using either SRTT19.5 or SRTT22.5 before 1 September 2028, and use SRTT19.5 siped or SRTT22.

Proposal to supersede document GRBP/2026/4 intended to introduce a “default mode”, to specify requirements to be applied to the emission of Enhanced Exterior Sound (EES), with 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).

The RD-ASEP informal group met in Brussels. Officers and representatives from eleven contracting parties and four NGOs were present. The group discussed copyright approval requirements for UN website materials. A February 2026 meeting with UNECE and ISO secretariats will address incorporating third-party standards into UN regulations. The Data Analysis Task Force reported on ESE in ICE vehicles and data limitations. Discussions covered vehicle control ranges, CVT handling, and vehicle category applicability. An issues list was established for draft regulatory text. The next meeting is scheduled for April 14-16, 2026 in Berlin.

The RD-ASEP informal group met in February 2026 in Geneva. The Analysis Task Force requested additional data on hybrids, CVT transmissions, and battery electric vehicles. The Editing Task Force addressed copyright issues with UN and ISO Secretariats, determining that current document practices continue unchanged. The group clarified that RD-ASEP development focuses on measurement procedures for real driving conditions and noise emission limits under full and partial load, not establishing a new regulatory phase.

ETRTO measurement uncertainties reduction efforts for UN R117 rolling sound emission test methods are progressing through outdoor and indoor Round Robin tests. Eight of thirteen outdoor test centres have completed tests for C₁ and C₂ tyres; remaining centres anticipate completion by mid-year. Indoors, two of six ETRTO test centres completed tests with others expected finished by mid-year. An intermediate report with available data will be presented in September 2026, full results postponed to February 2027, and the Working Document with test method evolution now expected in September 2027 instead of February 2027.

Proposal to amend Annex 3 of UN Regulation No. 51-02, paragraph 3.1.2.3.2.3, third paragraph, to require gear shifts beginning with (x/n) continue in all gears at which rated engine speed is reached immediately before the rear of the vehicle passes line BB’, rather than being completed in gear X only, based on WP.29-196-08 and WP.29-197-11 findings of non-compliance with permissible sound level requirements for category N₃G vehicles during state control testing.

ISO 362-3:2022 specifies an engineering method for measuring pass-by sound level of a vehicle under controlled indoor conditions using a semi-anechoic chamber. The 2022 edition incorporates technological advancements and improves usability and accuracy of the measurement procedure. Improvements include additional microphones, tire temperature correction harmonized with UN R51.03, clarified indoor room qualification criteria, and normalized torque influence equation. Transitional provisions propose accepting ISO 362-3:2022 for all approvals from entry into force of Supplement 11, while ISO 362-3:2016 remains accepted for five years thereafter.

Consolidation in Supplement 11 includes: clarification of Verification/Adjustment and editorial corrections with transitional provisions (GRBP/2025/20 with GRBP-82-07); correction of Tyre Road Sound Measurement for Indoor-Testing (GRBP-82-22); introduction of ASEP in Annex 7 for BEVs and HEVs (GRBP/2026/4 with GRBP-83-xx); update of ISO standards in Annex 3 and Annex 8 (GRBP/2026/5 with GRBP-83-xx); and reference for Power Definition regarding new UN R177 (GRBP/2026/13). The consolidated version of Supplement 11 is to be submitted to the 199th WP.29 in June.