Report on the Task Force on Tyre Abrasion’s work from February to October 2026. Foundational methodologies for C1 tyres were adopted and incorporated into a new UN Regulation 186 on tyre abrasion, with a two-stage implementation approach requiring new tyre type approvals from 30 June 2028 and mandatory approval from 30 June 2030, with fitting of pre-June 2030 tyres on vehicles permitted until 30 June 2032, and stage 2 introducing tighter limits with new approvals from 30 June 2033 and mandatory approval from 30 June 2035. C2 test method development is ongoing with an informal document presentation targeting February 2027 submission of a formal working document. For C3 tyres, a brainstorming session was planned for October 2026 in Brussels to develop simplified test methods before physical testing, focusing initially on long-haul and regional 22.5-inch tyres.
Draft UN Regulation establishing uniform provisions for type approval of electric powertrain retrofit systems (EPRS) for converting vehicles of categories M1–M3 and N1–N3 to full electric propulsion. Specifies approval procedures, application documentation, marking requirements, and technical specifications. Requires compliance with applicable UN Regulations including UN R10, UN R13, UN R100, and others depending on vehicle modifications. Defines roles of EPRS manufacturers and authorized installers. Includes transitional provisions for rechargeable energy storage system compliance: compliance with UN R100.03 required from entry into force to 31 August 2029, UN R100.05 from 1 September 2029. Covers conformity of production, modification and extension of approvals, and withdrawal procedures.
Status report on the EV/HFCV Retrofit Systems IWG activities. The group held six meetings since the last GRPE session and is currently focused on the EV part, with HFCV-specific issues deferred to a future series of amendments. Key discussion items include scope definition with agreement to exclude vehicles holding approvals according to UN R155 and UN R156, definition of Electric Powertrain Retrofit System, vehicle family notion, and type of EPRS. Experts from different GRs participate in discussions on electrical safety, EMC, braking, cybersecurity, and power determination. Benchmarking of existing national requirements for EV retrofit activities is ongoing. Regulation drafting continues on scope and type definition, with demonstrations of retrofitted vehicles expected at the 200th WP.29 session in November 2026.
The document authorizes development of a new UN GTR on brake PM and PN emissions from all types of light-duty vehicle brake systems, including validation of the developed novel WLTP-Brake test cycle, investigation and selection of instrumentation and sampling methodology for brake wear particles, definition of minimum requirements for sampling, validation through interlaboratory study, inclusion of regenerative braking, and preparation of the PMP Brake protocol. It also reports on Amendment 2 to UN GTR No. 24 covering laboratory measurement of brake emissions for light-duty vehicles, detailing hardware requirements, test cycle specifications, cooling air conditioning, bedding procedures, and emissions measurement methodologies for particulate matter and particle number.
Proposal to amend UN GTR No. 24 by modifying test procedures, definitions, and requirements for brake particle emissions measurement. The amendment introduces improvements including revised definitions (vehicle electrification type, material formulation, pad size), updated measurement tolerances and signal filtering requirements, provisions for brake filtering systems, enhanced specifications for drum and electromechanical brake systems, relaxed cooling airflow adjustment requirements, and a new test cycle for speed-limited vehicles. Documentation of calibration requirements and ongoing quality controls are clarified throughout.
Proposal to add para. 8.1.2. to specify required measurements for test vehicles, including use of onboard measurement data as an alternative to measurement devices for engine speed, intake manifold pressure, and fuel flow rate when accuracy and frequency meet minimum requirements, and to add para. 8.1.2.1. to specify measurements specific to TP1 including electrical current and voltage at REESS or inverter inputs and ICE speed, intake manifold pressure, and fuel flow rate.
Proposal to amend para. 3.1.2. of Annex 5 to clarify the verification procedure for SOCR/SOCE monitors by specifying that electric range and UBE values shall be measured at the time of verification with related monitor values collected before and after the verification test procedure, that indicator values collected after the verification test procedure shall not be considered in Part A verification, and that measured SOCR and measured SOCE values shall be determined by dividing measured values for electric range and UBE by certified values for electric range and UBE respectively, expressed in per cent.
Report on the third inter-laboratory study evaluating the repeatability and reproducibility of particulate emission factors using GTR 24 (1st amendment) across 14 laboratories worldwide. The study assessed laboratory proficiency in brake particulate matter and particle number emissions measurements for light-duty vehicles, testing two low-metallic brakes and one low-emitting NAO brake using the WLTP-Brake cycle. Inter-lab coefficient of variation for PM₁₀ was 10-15% for low-metallic brakes (4.5-8.5 mg/km emission levels) and 30% for the NAO brake (1.5 mg/km). Intra-lab repeatability for PM₁₀ was less than 5% for low-metallic brakes but higher for the NAO brake. A success rate of 94.8% was achieved after applying quality checks, confirming GTR 24 suitability for regulatory testing. The report provides recommendations for GTR 24 amendments including friction work calculation methodology, torque quality metrics, sampling probe setup standardization, and residual torque limits.
34. GRB noted that no new information had been given under this agenda item.