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.

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.

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.

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.

Proposal to establish a globally harmonised laboratory methodology for measuring brake particulate matter and particle number emissions from Heavy-Duty Vehicles. The UN GTR defines the test cycle (Worldwide Harmonized Heavy Duty Brake Cycle), minimum system requirements, test conditions, equipment preparation, brake dynamometer capabilities, brake enclosure design, sampling tunnel design, and sampling plane design. It applies to vehicles of categories M₂, M₃, N₂, N₃, and O₃, O₄ concerning braking, covering both friction braking systems (disc and drum brakes). The regulation includes requirements for brake bedding procedures, emissions measurements, calibration, and ongoing quality controls. A version with tracked changes is available.

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.

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.

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.

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.

The 56th PMP session convened online on 7 May 2026 with approximately 70 participants. Meeting minutes from 13 March 2026 were accepted. PMP agreed on a joint neutral template for all task forces. TF3a discussed cooling air adjustment, temperature criteria, and vehicle emission factors, with proposals requested by end of May 2026. TF3b will discuss family building and speed-limited vehicles. TF3c presented brake replacement parts activities. TF4 prepared work package B on electromechanical brakes and requested feedback by end of May 2026. TF5 reported progress on GTR on HD brake particle emissions with test campaigns planned. The next meeting is expected end of June or beginning of July 2026.

Task Force 5 is progressing on GTR development with tests on endurance braking ending 07/2026 and potential GTR adoption at GRPE 95th session 10/2026. Draft revisions to Sections 7 and 8 are agreed and incorporated, addressing caliper orientation, fixed airflow, and additional loading factor. Nominal test parameters for brake groups are under revision, with tables from R90 defining disc and drum brake specifications. A small Round Robin Exercise with five volunteers is underway to assess enclosure and duct diameter impacts, with results due first week of June. Auxiliary Braking Systems testing requires significant immediate effort.

The PMP webex meeting scheduled for 7 May 2026, 12:00-14:30 CET will review meeting minutes from 13.03.2026, provide an overview of amendments to Brakes GTR 24 and UN R179 covering layout and testing topics, vehicle limited speed, brake replacement parts, and electromechanical brakes, discuss GTR HD brakes, and address any other business.

The PMP session discussed revisions to the group’s terms of reference to address overlapping technical issues with GTR 24, UN R179, and replacement parts regulations. Three task forces were proposed: TF3a on layout and testing, TF3b on speed-limited vehicles, and TF4 on electromechanical brakes. Topics included non-original brake parts regulations, UN R179 amendments for new vehicle categories, and GTR heavy-duty brake particle emissions standards. The next meeting was scheduled for end of April 2026.

Proposal to establish a UN Global Technical Regulation for measuring brake particulate matter and particle number emissions from heavy-duty vehicles. The regulation defines laboratory test procedures using a brake dynamometer and the Worldwide Harmonized Heavy-Duty Vehicles Brake Cycle (WHBC), encompassing 20,353 seconds with 246 brake events across three driving segments. Tests require brake bedding with six WHBC repetitions, followed by emissions measurement. Laboratories must measure PM10 and PM2.5 mass gravimetrically and total and solid particle numbers (TPN10, SPN10) using particle counters. Technical specifications cover brake enclosure design, sampling tunnel configuration, climatic control, instrumentation calibration, and data reporting requirements to ensure reproducible and comparable brake emissions testing across regions.