The agenda includes discussion of status of the work plan 2026 including the ITTAC proposal on tyre abrasion Convoy Method -Dual-Normalisation Framework (TA-45-08/Rev.1) and UTAC Tyre abrasion timeline Gantt (TA-46-03/Rev.1), development of the C1 tyre mileage potential metric and tread depth measurement prescription, and test method development status under C2 and C3.
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 agenda includes transposition of UN-GTR 2 into UN R40, with discussions on Euro 4 level amendments, maximum power determination for two-wheelers, battery electric vehicle range standardization using SAE J2982 procedures, and deterioration factors in GTR 23.
Comments on the proposal for a03 series of amendments to UN Regulation No. 160. Modifications include renumbering paragraph 2.2 as paragraph 2.25, deleting paragraph 2.25, and amending definitions for “End of event time,” “Engine throttle, percent full,” “Non-volatile memory,” and other terms. New paragraphs 2.71–2.82 introduce definitions for rollover protection system, advanced emergency braking system, blind spot monitoring system, and driver assistance systems. Paragraphs 5.3.1, 5.3.2, and 5.3.3 are amended to clarify triggering and locking conditions for rollover events and vulnerable road user events, and to establish time zero. Paragraph 5.4.3 clarifies crash test requirements.
The agenda includes discussion of DSSAD regulatory text guidance, EDR Step 2 proposals comments, and EDR for ADS. The next meeting is scheduled for September 15-17, 2026, as a hybrid event in Europe.
Proposal to explain para. 8.3.3.1.1. The revised text clarifies that relevant standards supporting the assessment of laboratories could include ISO/IEC 17025 Testing and calibration laboratories, which sets requirements for competence, impartiality, and consistent operation. Applied to ADS testing, it ensures measurements are traceable, validated, and reproducible so results are technically reliable and defensible for approval/certification purposes. However, there is no obligation for the manufacturer or third-party organization involved in the testing to be accredited according to ISO/IEC 17025.
Proposal to explain para. 8.3.2.4.1.4. The revised text divides guidance between ADS users and other road users. For ADS users, representativeness means including a range whose behaviours, skills, and characteristics reflect those reasonably expected to use the ADS, with testing not limited to engineers. For other road users, representativeness means capturing a sufficiently broad range of real-world behaviours and characteristics relevant to the ODD. The revised proposal also addresses statistical significance, encouraging manufacturers to provide calculations explaining their choice of participant numbers and underlying assumptions.
Proposal to explain paragraph 8.3.2.1.2. The revision clarifies that coverage can be evaluated based on the following items and their interdependencies: Operational Environment, Behavioural competency, Scenario-type/category, and Rules of road compliance. A footnote acknowledges that no single item alone can robustly document coverage.
Proposal to align definitions across tyre regulations and align the regulations with technological progress (see document GRRF-82-21), correct an editorial error, and clarify that the ply rating is not applicable to T-type temporary use tyres.
GRBP will consider a proposal by the expert from the European Tyre and Rim Technical Organization (ETRTO).