Proposal to add, modify, and amend Annex 3, Annex 4, Annex 5, Annex 6, Annex 7, Annex 8, Annex 9, and Annex 10, insert Annex 9 (Measurement method to evaluate compliance with the Real Driving Additional Sound Emission Provisions (RD-ASEP)), and add provisions concerning sound emissions, test methods, measurement instruments, vehicle specifications, conformity of production, exhaust systems, compressed air noise, indoor testing, and specific provisions for vehicles equipped with an Automated Driving System (ADS).

Proposal to add, modify, and amend Annex 3, Annex 4, Annex 5, Annex 6, Annex 7, Annex 8, Annex 9, and Annex 10, insert Annex 9 (Measurement method to evaluate compliance with the Real Driving Additional Sound Emission Provisions (RD-ASEP)), and add provisions concerning sound emissions, test methods, measurement instruments, vehicle specifications, conformity of production, exhaust systems, compressed air noise, indoor testing, and specific provisions for vehicles equipped with an Automated Driving System (ADS).

The Task Force Data Analysis (Sub Group to IWG RD-ASEP) will hold its 12th meeting on Tuesday, 28th April 2026. The agenda includes a review of the meeting schedule with targeted meetings on 19th May, 3rd June, and 9th June, review of database version 3 status and input from Germany on database issues, review of analysis performed, and review of decisions and work for the next meeting.

The 21st session of the Task Force on Vehicles Sound will be held on Tuesday 9th June 2026 from 13:00 to 17:00 (CEST) as a hybrid meeting in Gothenburg, Sweden. The agenda includes adoption of the agenda and report of the 20th session, exchange of information on national and international requirements with presentations on anoise figures in vehicle certificates of conformity versus perceived noise" and on “transportation noise and cardiovascular health”, cross-matrix follow-up discussion, discussion on updating the guidelines of the task force as approved in GRBP-74-03 Rev.1, any other business, and determination of next meeting and provisional agenda.

The RD-ASEP Informal Working Group met April 14-16, 2026 in Berlin. The Analysis Task Force concluded data cleaning and will use data to answer questions and update the parameter table. The original aim of RD-ASEP was to address vehicles with louder partial throttle than full throttle results. The Editing Task Force reviewed draft R51.04 and was directed to provide an updated draft for the June meeting, replacing the old Annex 7 with the current Annex 9. The Chair requested the Editing Task Force prepare a summary report to GRBP for September evaluating the monitoring database, Expectation Model, and draft R51.04.

The Task Force Data Analysis held its 12th session on 28 April 2026. Database version 3 requires further corrections to reflect IWG decisions on v_test, parallel and serial hybrids, and German input; version 4 will be delivered. The group reviewed German input on database issues and decided to establish an Excel list documenting observations, background information, and proposed solutions. Additional data are needed on gear shifting during pass-by measurement, ICE ON/OFF shifting, low speed measurements below 30 km/h, high performance vehicles with acceleration greater than 5 m/s² at high speeds, and EV data.

Results of the review of proposals for UN Regulations R28, R51, R64, R138, R141, R142, and R165 regarding autonomous vehicle readiness. Key findings include: inconsistent Mass in Running Order definitions between R51 and R138 versus RE3; unclear special testing provisions in R64, R138, and R165; need for clarification on ADS optical and logical signal transition in R64; redundant full definitions from RE3 in multiple proposals should reference RE3 via footnote instead; inconsistent ADS activity terminology across R64, R141, and R165 should be standardized; incorrect Category Y references in R51 Table 2; and definition and spelling errors in R51, R138, R141, and R165.

The agenda for the 74th session of the Informal Working Group on Wet Grip of Worn Tyres scheduled for May 19th, 2026, remotely via Teams. The agenda includes welcome and opening remarks, adoption of the agenda and minutes of the previous 73rd session meeting held 31 March 2026, discussion of the workplan 2025 for C1 tyres status test campaign, and determination of the next meeting date.

The IWG RD-ASEP informal group is developing a mandatory procedure for UN R51 after the monitoring phase. The Analysis Task Force determined vehicle databases and expectation models are suitable for RD-ASEP development. The Editing Task Force created a consolidated R51.04 draft submitted to GRBP-84. The revised R51.04 RD-ASEP includes manipulation and defeat device provisions, mandatory random testing for approval, revised control range, any acceleration position testing, vehicle speed range 0-100 km/hr, and vehicle performance criteria. A revised companion document GRB-68-03 is necessary.

The Worn Tyres Post-Processing task force held its 34th session on 13 May 2026. Ninety-three percent of 3PMSF tests have been completed and members agreed to start the post-processing activity for the 3PMSF cluster. Test results for Normal tyres will be delivered once the high temperature range will be achieved. Future sessions are scheduled for 28 May, 15 June, 2 July, and 15 July 2026.

The 73rd session of the Informal Working Group on Wet Grip of Worn Tyres convened remotely on 31 March 2026. The agenda and previous session minutes from 3 February 2026 were adopted. The WTPP secretary reported on testing activities status for the workplan stage 1 for C₁ tyres, with results to be presented to GRBP at its 84th session in September 2026. ETRTO stated conclusions can only be made on complete datasets. Future meetings are scheduled through July 2026.

NEFOM and S.O.S. represent over 1 million European citizens experiencing noise from light vehicles inconsistent with Certificate of Conformity figures. The LENS project conducted 2300 measurements of 2300 vehicles, finding measured noise levels in practice much higher than type approval, sometimes reaching 100 dB(A). The A-filter used in Certificates of Conformity is unsuitable for noise levels above 70 dB and does not represent human perception. Sound limits for motorcycles have not changed since 2015 and remain too high. The document requests further improvements to RD-ASEP testing, replacement of the A-filter with a C-filter, and significant reduction of sound level limits for motorcycles.

Japan comments on the draft 04 series of amendments to UN R51 (Noise of M₁–M₃ and N₁–N₃ Categories of Vehicles). Japan highlights several editorial and technical issues. Regarding para. 2.24.1, Japan suggests the table of symbols for Annex 3 should state symbols are “used for the first time” consistent with ISO standards. For para. 3.1.2.1.4.3, Japan requests deletion of “but no more than 2.0 m/s²” as unnecessary for RD-ASEP applied to electric vehicles. Japan notes para. 6.2.3.4 should reference appropriate appendices for the RD-ASEP statement of compliance requirement. Paragraphs 11.1.4 and 11.1.5 are identical and one should be deleted. Japan flags para. 3.2.3.4.2 requires tyre conditioning on outdoor test tracks for indoor testing. For Annex 6, para. 3 should clarify that compliance assessment references para. 5 of Annex 7 for expected sound pressure level limits applicable to conformity of production testing.

During the 19th session

• OICA commented on LEON-T project reports regarding tyre and powertrain noise contributions.
• The European Environment Agency presented findings on transport noise exposure affecting over 100 million Europeans.
• Norway presented a proposed 95 dB(A) noise limit for stationary vehicles under UN R51.
• France proposed amending UN R28 to introduce soft audible warning devices for M and N category vehicles.
• The task force suspended its cross-matrix activity and postponed discussion of L-category vehicles to the next session.

The 20th session of the Task Force on Vehicle Sound convened on 14 April 2026. The session adopted the draft agenda and reviewed the 19th session report with a minor correction. The cross-matrix, defined in 2021 to assess traffic noise reduction policies through traffic scenarios and models, was rediscussed. A model based on RD-ASEP monitoring data was presented, showing significant deviations from EU-CNOSSOS predictions. Additional data are needed for M₃/N₃ and L-category vehicles. Extension of the cross-matrix to L-categories was proposed, utilising data from UN R41-06 RD-ASEP. A subgroup was established to develop scenarios, particularly for L-categories, and review available models. The next meeting is scheduled for 9 June 2026.

The session will cover database analysis including review of documents and discussion points from pilots view, AVAS term dL Dynamic factor x, review of decisions and work for the next meeting.

Draft minutes of the 74th session of the Informal Working Group WGWT held May 19th, 2026 (9:00–10:00 CET), remotely. Attendance per document WT-74-04. Agenda adopted. Previous meeting minutes of 73rd session (31 March 2026) not uploaded; to be adopted at next session per document WT-74-01. WTPP secretary updated on testing activities status per document WT-74-02. 3PMSF data from one test center pending before sharing anonymised data to WTPP for analysis. JASIC provided completed test data on 3PMSF and Normal tyres. Next meetings: WTPP 35 (28 May 09:00–10:30 CET); WTPP 36 (15 June 09:00–10:30 CET); 75th session (16 June 8:00–9:00 CET); WTPP 37 (02 July 09:00–10:30 CET); WTPP 38 (15 July 09:00–10:30 CET) per document WT-74-02.

Corrections to documents submitted by TF-AVRS and approved by GRBP amend terminology in UN R51.03 to harmonize bidirectional spelling, correct vehicle category references in UN R51.03 and UN R165 to reference category X only rather than non-existent category M1Y or category M, clarify in UN R64 that logical signals shall be transmitted to the ADS when an ADS feature is active, introduce references to specific ADS provisions in Annexes 5 and 7 of UN R138.02 and UN R165, add grammatical corrections to UN R141, and align UN R165 terminology with ADS regulation language.

The IWG RD-ASEP informal group is developing a mandatory procedure for UN R51 after the monitoring phase. The Analysis Task Force determined vehicle databases and expectation model are suitable for RD-ASEP use. The Editing Task Force created a consolidated R51.04 draft incorporating R51.03 Supplements up to Supplement 11, with revised manipulation and defeat device provisions and mandatory random testing for approval. R51.04 RD-ASEP expands vehicle speed range to 0-100 km/hr, adds vehicle performance criteria, requires testing for approval, and permits random test points and any acceleration position, compared to R51.03 ASEP.