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

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.

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.

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.

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.