Explanatory document on proposed amendments to UN R168 to enable real driving emissions testing of hydrogen internal combustion engine vehicles. The work-based approach replaces the CO-based moving averaging window methodology currently inapplicable to hydrogen-fuelled vehicles. Engine speed and torque data replace carbon monoxide to define window size and calculate the RDE/WLTP work ratio. Testing of a light commercial vehicle demonstrates the methodology’s practical applicability under regular and severe driving conditions, with results processed through independent post-processing tools.

Proposal to establish uniform provisions for approval of non-original replacement and identical brake pads, drum brake linings, brake discs, and brake drums for vehicles of category M₁, N₁, and N₂ between 3.5 and 5 tonnes maximum mass. The regulation applies brake emission testing procedures and particle emission limits by vehicle category and powertrain technology, with PM10 limits ranging from 3 mg/km for PEV vehicles of categories M₁ and N₁ to 11 mg/km for N₁ Class III and N₂ vehicles. Brake parts must be assigned to families based on characteristics including calliper type, axle location, friction material formulation, disc or drum material, brake disc surface form, pad surface area, and drum diameter. Approval requires testing of a family parent brake assembly and includes conformity of production requirements with annual sampling and statistical verification procedures.

Progress report on Particular Matter Pollutants (PMP) Informal Working Group activities for GRPE-95. Updates on proposals for a new Supplement to UN R179, a new UN Regulation on brake replacement parts, additions to GTR 24 for light-duty vehicles with limited speed, a new GTR for heavy-duty brakes, and a new UN Regulation for heavy-duty vehicle brakes. Reports on ongoing inter-laboratory studies for calibration procedures and brake emissions testing. Discusses technical developments in brake testing facilities, electromechanical brakes, and conformity of production procedures.

Overview of documents and working party activities for the 95th session of the Working Party on Pollution and Energy (GRPE). Documents address improvements to UN R179 (Laboratory Measurement of Brake Emissions for Light Duty Vehicles) including handling of vehicles with limited speed, brake replacement parts regulation, and GTR 24 (Measurement procedures for Brake corner emission factors). Related documents also cover a new regulation for heavy-duty brake emissions and a new global technical regulation for heavy-duty brakes. Working documents ECE/TRANS/WP.29/GRPE/2026/29, ECE/TRANS/WP.29/GRPE/2026/30, ECE/TRANS/WP.29/GRPE/2026/31, ECE/TRANS/WP.29/GRPE/2026/32, and ECE/TRANS/WP.29/GRPE/2026/53 are submitted.

Proposal to establish a UN Regulation for laboratory measurement of brake particle emissions from vehicles of categories M₂, M₃, N₂ and N₃ using friction braking systems. The regulation specifies test procedures including brake bedding and brake emissions measurement using the Worldwide Harmonized Heavy Duty Vehicles Brake Cycle, defines brake emissions groups and representative configurations for testing, establishes emission limits by vehicle category and powertrain technology (though limits marked as ‘not yet specified’ in the provided draft), requires conformity of production testing with statistical verification procedures, and sets technical requirements for brake dynamometer systems, brake enclosure design, sampling tunnels, cooling air conditioning, particulate matter and particle number measurement systems, and data acquisition.

Phase 2 of the DfT Brake and Tyre Programme investigated variables affecting particle emissions from brake and tyre wear. Testing compared three vehicles on the same Golf VII platform (ICE, PHEV, EV) at different masses using controlled chassis dynamometer cycles. Results showed regenerative braking in EV and PHEV reduced PM2.5 more effectively than a ~20% mass reduction, while PN10 emissions remained similar across vehicle types and were insensitive to mass or regenerative braking. Testing of brake pad and disc variants found ceramic and low-dust pads gave lowest emissions, while high-mileage pads reduced PM2.5 but not PN10. PM2.5 and PN10 appear governed by different mechanisms, with volatile chemistry of brake pads being critical for PM2.5 emissions.

Round Robin exercise 2 evaluated detection efficiency and calibration variability of condensation particle counters (CPCs) at 23 nm and 10 nm across eight laboratories using multiple calibration materials including emery oil, soot, silver, and graphite particles. Measured variability was better than 5% at plateau and around 5% at 23 nm. Material differences from soot at 23 nm ranged from −0.04 to 0.41 units depending on the particle type. Preliminary recommendations include continuing with emery oil for continuity, applying generator/CPC type-specific correlation factors determined by manufacturers when different materials are used, and conducting annual validations with the same material.

Proposal to amend GRPE/2026/29, establishing a globally harmonized laboratory methodology for measuring brake particulate matter (PM) and particle number (PN) emissions from heavy-duty vehicles of categories M₂, M₃, N₂, N₃, and O₃, O₄.

Draft Minutes of the 56th Particle Measurement Programme session held online on 9th July 2026, 12:00-14:30 CET. The meeting reviewed amendments to Brakes GTR 24 and UN R179 across five task forces. TF3a presented layout and testing topics with concerns raised regarding repetition increases and force distribution. TF3b discussed vehicles with limited speed and family classification issues. TF3c addressed brake replacement parts and emission limits. TF4 reported on electromechanical brakes with work package B agreed. TF5 presented the GTR on heavy-duty brake particle emissions with results expressed in mg/km, with some points remaining in brackets pending inter-laboratory comparisons. Comments are due by 16th July, with the next meeting expected mid/end of September 2026 and a hybrid PMP meeting planned for 12th or 13th October in Geneva.