The UN IWG for Children Left in Vehicles is in Phase 2 developing a new UN Regulation for vehicle categories M₂ and M₃. The draft UN Regulation includes requirements for visual and audible external warnings in buses and coaches to prevent children being left inside. The external warning shall be visual and audible, with the visual warning remaining on for at least 15 seconds then off for no greater than 30 seconds, repeating in cycles lasting no less than 10 minutes, using type approved direction indicator lamps all flashing with the same frequency. The audible warning shall remain on for at least 15 seconds then off for no greater than 30 seconds, repeating in cycles lasting no less than 10 minutes, and shall be greater than 60dB(A). Both warnings shall stop immediately after the physical inspection system is disarmed or the vehicle master control switch is turned on. The IWG intends to permit audible devices approved to UN Regulation No. 28 or UN Regulation No. 165 to generate the external audible warning.

Minutes of the 75th session of the Informal Working Group WGWT held 16 June 2026 on-line. The agenda was adopted. Previous meeting minutes from the 73rd session (31 March 2026) and 74th session (19 May 2026) were adopted. WTPP secretary updated on testing activities status per document WT-75-2. ETRTO stated the agreed number of tests was a statistical minimum and IWG WGWT conclusions to GRBP must be based on complete test results. IWG WGWT agreed to await WTPP conclusions on outliers before deciding whether to keep the current number of tests or make additional tests. The co-chair stated a status report must be prepared for GRBP 84th session (September 2026) and suggested an IWG WGWT meeting days before GRBP. Next IWG WGWT meeting scheduled for 28 August 9:00–10:00 CET.

Proposal to amend Annex 3 and Annex 7 regarding ASEP calculations and temperature corrections:

• Add reference to nMAX and kp factor for ASEP anchor point calculation in Annex 3, Appendix 1 Table 1,
• Clarify temperature correction equations and coefficients K1 and K2 by defining them uniquely in para. 3.2.3. and adding missing index j references in Annex 3, Appendix 2 paras. 3.2.3., 3.2.4., 3.3.3. and 3.3.4.,
• Delete from Annex 7 para. 5.2. a sentence regarding gear ratios for ASEP Lref that was wrongly introduced in Supplement 10 (GRBP-79-33/Rev.1).

The Worn Tyres Post-Processing task force completed data collection for 3PMSF and Normal tyres, each with 57 samples representing 100% of target. Ongoing activities include outliers analysis of the 3PMSF and Normal cluster and post processing of the data conclusions.

Proposal to amend UN R51 in the 04 series of amendments based on GRBP-84-07, adding definitions and specifications for Real Driving Additional Sound Emission Provisions applying to vehicles of categories M₁ and N₁, modifying sound measurement methods and test procedures including indoor testing provisions, establishing a sound expectation model for RD-ASEP compliance evaluation, introducing provisions for vehicles equipped with an Automated Driving System, and updating Annexes 3 through 10 and associated appendices with revised test conditions, gear selection flowcharts, temperature and test-track corrections, tyre rolling sound measurement procedures, compressed air noise assessment, and conformity of production checks. No Contracting Party shall refuse to grant type-approvals under the 04 series of amendments from its entry into force until [TBD date], after which approvals under the preceding 03 series may no longer be accepted.

The IWG RD-ASEP Informal Group is developing a mandatory test procedure for UN R51 to assess vehicle noise emission compliance under conditions other than Annex 3, ensuring no defeat device schemes exist. The Editing Task Force created a consolidated R51.04 draft incorporating Supplements up to Supplement 11, with mandatory random RD-ASEP testing for approval and revised control ranges. R51.04 RD-ASEP expands vehicle speed range to 1-100 km/h, adds vehicle performance criteria, implements random test points, and requires testing for approval. Working document submission is expected September 2027, with expected adoption February 2028.

Proposals for earlier series of amendments those may be used in certain country
where R156-01 is required. The provisions regarding provision of information on hardware and software relevant to approval testing are moved to the section related to specifications and/or tests as instructed in R.E.3. and the amendment made by WP29-197-06 is reflected.

The UN IWG for CLIV is in Phase 2 on developing a new UN Regulation on Children Left in Vehicles (CLIVs) for vehicle categories M2 and M3. The draft UN Regulation includes requirements with regards to visual and audible external warnings in buses and coaches to assist in the prevention of children being left inside. The IWG has prioritized the development of a new UN Regulation for buses and coaches in the first instance.

Proposal to amend Annex 7, paragraph 3.1, to add provisions allowing discard of test runs when additional operating conditions lead to riding conditions not expected to occur in real traffic such as front wheel lift up, apparent wheel spin, chain slap, or engine lugging, and amend paragraph 3.2.2 to specify that if unusual riding conditions occur during testing, the test shall be performed in the next higher gear and maximum vehicle speed shall be reached at line BB’ instead, thereby ensuring consistency with the 05 and 06 series of UN Regulation No. 41.

Draft agenda of the 76th session of the Informal Working Group WGWT scheduled for August 28th, 2026 on-line. The agenda includes welcome and opening remarks, adoption of the agenda, adoption of the minutes of the 75th session of 16 June 2026, review of work plan 2025-2026 for C1 tyres, review of IWG WGWT status report for GRBP 84th session of September 2026, and next meetings.

The IWG for Wet Grip on Worn Tyres reports progress on evaluating methods for preparing tyres of Class C1 to be tested in worn state at type-approval, defining test conditions and methods, establishing type-approval thresholds for wet grip performance, and addressing requirements for classes C2 and C3. Test Campaign Stage 1 assesses test procedure precision per GRBP-80-11, with normal and 3PMSF tyres completely tested at 13 test centres. Outliers analysis and KPI target confirmation are ongoing. Stage 2, if needed, is planned for 2026-2027.

Proposal to solve the discrepancies between the test report format and the description of the test method for C2 and C3 tyres.

Proposal replaces the GRBP2026/26

Road legal race tyres are currently defined in the new UN R186 on abrasion but fall out of its scope. Considering that the new UN R186 on abrasion applies only to tyres that conform to UN Regulation No. 117., it is proposed to replicate therein the definition, the marking and the requirements of road legal race tyres by adding the new paragraphs 2.21., 4.5. and 6.9.

Proposal for a Guideline regarding the Interpretation of Paragraph 6.2.3. ASEP in the 03 series of amendments to UN Regulation No. 51, updating Informal Document GRB-68-03 and based on GRB/2005/5 and GRB/2010/9. Part A addresses internal combustion and hybrid vehicles when the combustion engine is operating, defining typical on-road driving as vehicle speeds between 15 km/h and 100 km/h, accelerations not exceeding 2 m/s² and vehicle performance not exceeding 35 m/s², and engine speeds of at least 1.5 times idle speed and not exceeding the maximum outlined in Annex 7. Significant deviation means sound level exceeding reference values by at least 6 dB(A). Type approval test results derive from Annex 3 or Annex 7 values, with reference values established using regression curves or calculation principles. Part B addresses electric and hybrid vehicles propelled electrically only, extending guidance to electrified vehicles and Enhanced Exterior Sound introduced by Supplement 11. Typical on-road driving for electric vehicles includes vehicle speeds greater than 0 km/h and up to 100 km/h and standstill covered by UN-R 138. Significant deviation for electric vehicles is at least 3–6 dB(A).

The agenda includes welcome and opening remarks, introduction of participants and organizations, adoption of the draft agenda, review of minutes from the 13th session of June 2026, review of Terms of Reference from GRBP 78th Session (GRBP-78-13), UN R51 matters, review of report to GRBP, and determination of the date and place of the next meeting, scheduled for 20–22 October in Barcelona, Spain.

Progress Report (February 2026 – September 2026)
Conclusion of work on UN Regulation on tyre abrasion for C1 tyres, launch of C2 work, outlook for C3 work

RD-ASEP includes technical background and vehicle application guidance for Real Driving Additional Sound Emission Provisions under UN R51.03 Supplement 7 Annex 9 for the mandatory monitoring phase between 07/2023 and 06/2024. RD-ASEP, referenced in GRB-68-03, applies to vehicles of category M₁ and N₁ equipped with internal combustion engines and covers engine speeds up to 95% of typical driving in speed ranges applicable to sub-urban conditions. A Sound Expectation Model predicts vehicle sound levels at randomly selected operation conditions by splitting measured pass-by test results into tyre rolling sound, mechanical no-load sound, and dynamic sound components, using reference values from Annex 3 type approval tests with logarithmic functions and parameter table slopes. Compliance assessment allows measured sound to exceed calculated expected sound by not more than 2 dB for maximum two test runs out of fifteen. Model validation with 2024 monitoring database confirms the tyre rolling sound and power train sound models represent well approved tyres and engines, with less than 5 dB typically separating pass-by run results from the limit.

An improvement intended to increase vehicle robustness in Annex 3 creates more difficulties in RD-ASEP assessment. Small variations in Annex 3 parameters may result in unexpected substantial exceedances in Annex 7. Minimal changes in the calculated tyre share at the anchor point may cause vehicles to fail Annex 7. The regulation should ensure realistic test effort and workload for compliance verification, as current requirements may require up to 180 combinations per type across test tracks, temperatures, driving modes, and tyres.