The 76th session of the Informal Working Group on Wet Grip of Worn Tyres convened on 28 August 2026 remotely. The agenda was adopted and previous meeting minutes from the 75th session were adopted. The WTPP secretary updated the IWG WGWT on testing activities status; the Co-chair noted the Gantt should reflect additional postprocessing time extending to September 2026. The Co-chair presented the status report for GRBP 84th session, with an ETRTO expert proposing clarification of the word outlier. A revised status report will be sent to GRBP secretariat. Next meetings are scheduled for 11 August, 14 September, and 28 October 2026.
JASIC submits comments on ETRTO analysis results for the worn tyre wet performance test precision improvement study. JASIC argues that 2019-2021 test campaign data is not acceptable for Stage 1 analysis because it used buffed SRTT rather than the molded SRTT prerequisite, original sample sizes of n=4 per SKU were reduced to n=2 or n=1 after excluding NOK data rendering statistical analysis unreliable, and the data falls outside Stage 1 assessment scope. JASIC recommends not using 2019-2021 data for weighted assessment, proposes defining M+S tyre coefficients by averaging 3PMSF and NORMAL coefficients, and recommends revising GB calculation formula coefficients for trailer method based on Stage 1 data.
Test precision weighted analysis to exclude NOK data from the worn tyre wet performance test. Analysis of precision using dataset without NOK data shows the same trend as analysis based on full dataset. New coefficients for the GB formula significantly improve precision, which is now comparable to new tyre wet grip test. Strong correlation exists between current and new formulas, making it possible to continue current worn-tyre wet grip criteria. JATMA proposes to revise coefficients of the GB calculation formula based on Stage 1 data.
JASIC presents Stage 1 findings on worn tyre wet performance testing precision improvement. JASIC proposes that the KPI target should be the same weighted value as wet grip for new tyres (100% improvement), compared to ETRTO’s 50% improvement target. Stage 1 weighted analysis results show 50% improvement, or 100% improvement if coefficients of the GB formula are revised. The 2019-21 dataset is outside Stage 1 assessment scope due to unmet prerequisites such as buffed SRTT tyre application and reduced sample sizes. JASIC proposes revising GB calculation formula coefficients for the trailer method based on Stage 1 data, with continuous investigation to follow.
Agenda for the kick-off meeting of the Task Force on Exchange of Scenario-Relevant Information (ESRI) scheduled for 17 December 2026 via web conference. The meeting will include welcome and opening remarks, adoption of the agenda, presentation of the rationale and Terms of Reference adopted by the 26th GRVA, presentation of the Task Force’s work perspectives and timeline for 2027 including expected achievements and key deliverables, invitations for dedicated presentations from Contracting Parties and non-governmental organizations on their contributions and ongoing work on scenarios, requests for participant feedback and priorities for 2027, and concluding remarks with agreement on next steps.
Proposal to amend UN Regulation No. 51 concerning approval of motor vehicles with regard to sound emissions. The document provides comprehensive specifications for noise measurement methods and limits for vehicles of categories M and N, including:
Global Technical Regulation