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 4 addresses brake system development towards dry brakes, specifically electromechanical brakes. Current methods to determine friction brake torque available for hydraulic systems are not all applicable for dry systems. Task Force 4 targets defining a pressure-based equivalent method for electromechanical brake systems and reviewing document validity for electromechanical braking systems. Work Package B completed text document review with proposed changes due end of May 2026. Work Package A discusses two alternative approaches for c-factor calculation: clamping force based and recuperated energy based, with verification tests planned by end of June 2026.

PMP Task Force 3b held kick-off on 07.05.2026 to address vehicles with legal limited speed, vehicles unable to follow cycle trace, and vehicles with capped speed by OEM decision. Proposals include adaptation of UN R179 cycle and procedure for vehicles with legal limited speed at 90 kph, with same duration for acceleration, cruise, and deceleration events, same acceleration and deceleration rates, and speed capped when needed. Introduction of such vehicles into brake corner emission families and vehicle types requires methodology to calculate adapted cycle and procedure, including c-factor measurement as alternative to fixed c-factor, and adaptation of Annex 5 procedure.

PMP TF 3a is consolidating and updating UN R179 and GTR 24 through weekly web-meetings organized by JRC with 30+ participants. Over 50 topics have been identified and categorized by priority. Key issues include aligning Type Approval and Conformity of Production testing procedures, harmonizing cooling air adjustment requirements, clarifying vehicle c-factor calculations, adding definitions for light-duty vehicles exceeding 3.5 tonnes, and addressing test wheel load per GRPE-94-15e. The task force is preparing track changes versions and supporting documentation for major changes.

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.

Proposal to amend UN R179 Supplement 1:

• Modify the scope to include vehicles of category N₂ between 3.5 and 5 tonnes maximum mass at manufacturer request
• Add abbreviations and definitions including “Category M₁ vehicle”, “Mass in running order”, “Service brake”, “Brake calliper”, “User-selectable mode”, “ADS user”, and “Vehicle user”
• Amend the reference method to require testing on WLTP-Brake cycle using UN R154 compliant chassis dynamometer with external sensors for brake torque
• Specify vehicle selection procedures for testing user-selectable modes resulting in lowest recuperation with possible exemptions for very special limited purposes modes

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 clarify the selection of the wheel load among vehicles with identical brake assemblies for particle emissions testing.

Proposal to enable the approval of vehicles equipped with an Automated Driving System under the new UN Regulation on brake particle emissions.