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.
Presentation on brake inertia determination for potential amendment to heavy-duty brake emission protocol. Currently proposed protocol assumes test inertia determined based on UN R90, but comparison with C-factor from vehicle testing showed significant differences in inertia and actual load during dynamometer testing, with front and rear values differing by up to 2.3 times. Proposes retaining UN R90-based approach as default method while adding alternative inertia determination method considering vehicle mass and multi-axle configurations. Analysis of 43 Japanese market vehicle models showed UN R90-based approach can result in brake loads ranging from 0.1 to 5.7 times those of vehicle-based approach.
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.
Document outlining the 1st DETA/IWVTA Workshop held on 17 June 2026 in Flensburg, Germany. The workshop covered presentations on what DETA and IWVTA are, industry and government expectations, and issuance and acceptance of IWVTA certificates in the EU. Survey responses from 15 participants, including from Southeast Asian countries, indicated needs for more explanation on DETA access rights, onboarding processes for new Contracting Parties, and clearer guidance on how IWVTA can be modified to suit individual markets. Suggestions included developing supporting materials and guidelines on IWVTA application procedures and organizing a second workshop in Japan or Asia.
GRSP sought WP.29 guidance on an apparent contradiction between transitional provisions 15.1.2. and 15.1.3. in the 06 series of amendments to UN R22 (helmets) and article 12.4 of Revision 3 of the 1958 Agreement. WP.29 agreed that the provisions of the 1958 Agreement should prevail over those of specific UN Regulations and that these transitional provisions are invalid, even though the 06 series entered into force on 3 January 2021 after Revision 3 of the 1958 Agreement entered into force on 14 September 2017. Article 12.4 applies to all UN Regulations regardless of date of issuance and preserves each Contracting Party’s freedom to choose whether to accept type approvals issued pursuant to earlier versions.
Working text as updated during the 24th task force session.
Copy of document GRVA-17-49.