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.

TF5-SG2 update on GTR HD brakes test cycle development. Phases include analysis of measured brake cycles from real world data, adjustment of VECTO driver model to meet real world distributions, integration of endurance brake model, and shortening VECTO mission profiles to test cycle candidate. SG2 decided to use VECTO cycles as basis, resulting speed cycle for optimisation, and cycle without road gradients. Next steps include elaborating method to calculate torque and rpm from speed cycle, further shortening cycle to approximately 4 hours, and testing cycle to elaborate quality criterion for reproducibility. Volume flow settings on HD brake dynos require elaboration in SG1.

Proposal to establish sampling plane diameter of 300 mm or 12" with wall thickness of up to 1.5 mm, specify sampling tunnel straight section length between 8D and 10D, require single sampling plane layout with two PN probes on top and two PM probes on bottom, allow 4-probe sampling plane with flow splitter for PN connections only, prohibit flow splitter use for PM connection, permit sampling tunnel attachment directly to enclosure outlet or to 90-degree bend after enclosure, and standardize disc brake adapter and fixture and reduce drum brake S-cam length.