PMP webex meeting scheduled for 9th July 2026, 12:00–14:30 CET. Agenda includes an overview of amendments to Brakes GTR 24 and UN R179, task force discussions on layout and testing topics, vehicles limited speed, brake replacement parts, electromechanical brakes GTR and UNR, HD brakes, projects on tyres and brakes, and any other business. Webex meeting access details and link provided.

This document proposes a new UN Global Technical Regulation (UN GTR) for measuring brake particle emissions from Heavy-Duty Vehicles (HDVs). The GTR establishes a harmonised laboratory methodology covering the Worldwide Harmonised Heavy-Duty Vehicles Brake Cycle (WHBC), test system requirements, and measurement protocols for particulate matter (PM) and particle number (PN) emissions.

Key substantive elements include:

- Scope covering M₂–M₃, N₂–N₃, and O₃–O₄ category vehicles with friction braking systems
- Detailed specifications for brake dynamometer systems, enclosure design, sampling tunnel geometry, and cooling air conditioning
- Definition of the WHBC comprising three segments (urban, rural, motorway) with 246 brake events over 20,353 seconds and 271 km
- Brake bedding procedure (six consecutive WHBC cycles) followed by a single WHBC emissions measurement section
- Requirements for PM₁₀ and PM_2.5 gravimetric sampling using cyclonic separators and filter-based collection
- Requirements for TPN₁₀ and SPN₁₀ measurement using dilution systems and particle number counters with specified PCRFs
- Detailed quality checks including speed violations, brake event count verification, and kinetic energy dissipation tolerances
- Comprehensive calibration requirements for dynamometer, flow measurement, weighing equipment, and sampling/measurement devices
- Test output specifications including Event-Based, Time-Based, Mass Measurement, and Test Report files

The regulation applies a friction braking share coefficient to convert reference emission factors from the tested brake to final emission factors applicable to the vehicle.

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.

Task Force 3b addresses vehicles with limited speed by introducing a new Appendix 3 in Annex 4 to calculate adjusted cycles when vehicle maximum speed is lower than the WLTC-Brake cycle. The proposal modifies brake corner emissions family testing to allow vehicles with limited speed to be included in families with standard vehicles, with emission factors calculated from parent family factors or measured on adjusted cycles. Amendments address c-factor measurement, cycle-adjusted brake events, kinetic energy dissipation tolerances, and report file specifications.

Task Force 5 progressed toward GTR adoption planned for GRPE 95th session in 10/2026. JRC endurance braking tests conclude 07/08/2026. A small round robin exercise with six participants tests three airflow settings to finalize bracketed values. Key updates include maximum sampling probe length of 1.35m, PM10 probe positioning on outside streamline for bent layouts, and probe distance reduction from 100mm to 70mm. Proposal to delete the Disc or Drum Metallurgy for Brake Groups section. Final GTR text requires PMP comments by 22/07/2026, with layout decisions by 16/07/2026. UNR drafting based on UN R179 skeleton has commenced with significant work required.

TF 3c addressed brake emission of replacement parts. Proposed amendments include clarification that surface heat-treated discs fall under “other” category, refinement of “Brake Emissions Family Parent” definition, and addition of new appendix to UN Regulation No. 179 Annex 2. Data sharing agreement established: front-to-rear axle emission ratio, brake force distribution, and vehicle electrification type will be shared with aftermarket operators. Two approaches for aftermarket applicants: use vehicle-specific data through benchmarking or bilateral agreements, or apply default values from Tables 5.4 and 5.5. Testing revealed up to 30% variation within friction-couple families. Safety factor application when using actual c-factor values remains under discussion, with final decision expected before October.

Task Force 4 has completed revisions to GTR 24 concerning electro-mechanical calipers and proposes to include them in Amendment 3.

Proposal to amend UN R179 following GRPE-94-15e:

• Include supplements on automated vehicle definitions and OICA proposals on family members with higher wheel load but lower wheel load times c-factor ratio,
• Clarify wheel load and vehicle mass definitions for different tests,
• Add wheel load distribution for light commercial vehicles with fully laden mass between 3.5 and 5 tonnes,
• Redefine brake assembly to allow brake calliper reuse if in technically suitable condition,
• Optionally omit cooling air adjustment if temperature requirements are fulfilled,
• Require three emission measurement sections instead of one for type approval with arithmetical average reported,
• Clarify energy calculation for vehicles with limited speed,
• Harmonize reporting requirements including units and decimals,
• Define normalized flows,
• Include transitional provisions stating that vehicle types with existing valid type approvals issued before entry into force of supplement 2 need not undergo new type approval testing.

This document proposes a new UN Regulation on uniform provisions concerning approval of non-original and identical replacement brake parts regarding particulate emissions. The regulation applies to laboratory measurement of brake emissions from non-original replacement brake pads, linings, discs, and drums for vehicles of categories M₁, N₁, and N₂ originating from vehicles with type approval under Regulation No. 179. Approval requires emission factors to comply with specified limits based on vehicle category and powertrain technology. The regulation establishes brake emissions families based on characteristics including calliper type, vehicle axle location, friction material formulation, brake disc or drum material, disc surface form, friction material surface area, and drum diameter. Testing procedures, conformity of production requirements, marking and packaging specifications, and approval extension procedures are detailed.

Proposal to insert new paras. 3.3.29. to 3.3.33. defining “Semi-Metallic-Organic,” “Low-Steel-Organic,” “Non-Asbestos-Organic,” and “Low-Steel-Non-Organic” friction materials and “Pad area,” amend Annex 2 title to read “Annex 2 Communication,” insert a new footnote to Annex 2, and insert a new Annex 2 – Appendix containing a list of vehicle data for UN Regulation No. [XXX] approvals including vehicle type description, brake linings and discs specifications, vehicle test mass, maximum speed, tyre dimensions, brake circuit configuration, and brake specifications.

Agenda for a PMP webex meeting on 29 September 2026 to review meeting minutes, overview amendments to GTR 24 and UN R179 on brakes across multiple task forces covering layout and testing topics, vehicles limited speed, brake replacement parts, and electromechanical brakes, discuss GTR and UN R heavy-duty brakes, and address any other business.

Overview of working documents for the 95th session of GRPE, listing five working documents on new GTR for heavy-duty brake emission, UN R179 second supplement, GTR 24 third amendment, vehicles with limited speed for UN R179 and GTR 24, and new UNR on emissions covering brake replacement parts, with informal documents to follow from clean working documents.

Progress report on development of a Global Technical Regulation for brake emissions testing. The document presents bracketed parameters under development including brake test temperature measurement, sampling plane positioning, brake enclosure dimensions, payload factors, and emission factor calculations. It outlines the structure of the informal document based on UN R179, defines endurance braking systems and electric regenerative braking, presents C-factor methodology for primary and secondary endurance braking, and describes conformity of production procedures and next steps including removal of brackets and round-robin data analysis.

Proposal to improve and correct the procedure for laboratory measurement of brake emissions for light-duty vehicles of categories M₁ and N₁. The regulation establishes requirements for brake particle emission testing including test setup, the WLTP-Brake cycle test procedure, cooling air adjustment, brake bedding, and emissions measurement sections. Compliance is demonstrated through brake corner emission family testing with PM₁₀ and SPN₁₀ measurements. Conformity of production is verified through periodic sampling and statistical evaluation. Type approval requires demonstration that whole vehicle brake emissions calculated from individual axle emissions multiplied by friction braking share coefficients do not exceed limits of 3 mg/km PM₁₀ for M₁ and N₁ vehicles and 5 mg/km for N₁ Class III and N₂ vehicles.

Meeting minutes documenting PMP discussions on amendments to Brakes GTR 24 and UN R179, including TF3a layout and testing topics, TF3b vehicles limited speed work, TF3c brake replacement parts with a new UNR to be introduced, and TF4 electromechanical brakes with no further progress. GTR and UNR informal documents on HD brakes were presented with trailers removed from scope, open points on PM Emission Factor units, caliper position, test input parameters, and cooling air flow value addressed, and a 3-month delay in round robin testing reported.

Editorial corrections to the Appendix and reference to Annex 4.

Agenda items include review of meeting minutes, overview of amendments to Brakes GTR 24 and UN R179, HD brakes and inertia considerations, projects on tyres and brakes including brake emissions from Phase 2 of the DfT Brake and Tyre Emissions Programme and characterization of brake particle emissions from electric vehicles, preliminary results of CPC inter-laboratory exercise on calibration materials, and any other business.

Draft amendments to the proposal to improve and correct the procedure for measuring laboratory brake emissions on light-duty vehicles (GRPE/2026/30). The document establishes scope and application for vehicles of category M₁ and N₁, defines abbreviations and symbols, sets compliance requirements with emission limits for PM10, and specifies test procedures including cooling adjustment, brake bedding, and emissions measurement sections using the WLTP-Brake cycle. It addresses brake corner emission families, type approval requirements, conformity of production testing at least once every 12 months with statistical pass/fail decision charts, and conformity assessment through verification procedures.

Draft amendments to the proposal to include testing of vehicles with limited speed (GRPE/2026/32). The document provides specifications for brake emissions testing including test-system requirements, climatic conditioning, brake dynamometer setup, sampling procedures, and data analysis methods for measuring particulate matter and particle number emissions from friction brake systems on light-duty vehicles.

Proposal to amend GRPE/2026/31 revising the methodology for measuring brake particle emissions from light-duty vehicles.