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.

Proposal to establish a new supplement to UN Regulation No. 179, improving and correcting brake emissions measurement procedures for light-duty vehicles of categories M₁ and N₁. The regulation applies full-friction braking testing on brake dynamometers using the WLTP-Brake cycle comprising ten trips and 303 brake deceleration events. Testing includes three sections: cooling air adjustment, brake bedding with five cycle repetitions, and emissions measurement with three cycle repetitions. Compliance is demonstrated by measuring PM10 and SPN10 emissions from brake corner emission family parents, with whole-vehicle emissions calculated using friction braking share coefficients specific to vehicle electrification types. PM10 limits are 3 mg/km for M₁/N₁ vehicles and 5 mg/km for N₁ Class III/N₂ vehicles. Conformity of production requires annual testing of brake corner emission families with statistical evaluation per decision charts through 31 December 2029 (Phase I, PM10 only), with Phase II from 1 January 2030 evaluating both PM10 and SPN10. A version of this document with tracked changes is available.

Proposal to modify UN GTR No. 24 with respect to laboratory measurement procedures for brake emissions of light-duty vehicles. This amendment improves and corrects the testing procedure, including detailed requirements for test system setup, cooling air conditioning, brake dynamometer specifications, WLTP-Brake cycle execution, emissions measurements for particulate matter (PM2.5, PM10) and particle number (TPN10, SPN10), calibration protocols, and reporting of results. The regulation defines brake corner emissions families, friction braking share coefficients for different vehicle electrification types (ICE, HEV categories, PEV), and test procedures using fully-enclosed brake dynamometers with isokinetic sampling systems. A version with tracked changes is available.

Proposal to include testing of vehicles with limited speed. The document sets out the laboratory measurement procedure for brake emissions from light-duty vehicles of categories M₁ and N₁, including vehicles with maximum speed below the Base cycle maximum speed. Testing involves three sections: cooling air adjustment, brake bedding with five repetitions of the WLTP-Brake cycle, and brake emissions measurement with one WLTP-Brake cycle. Brake corner emission families are tested on a component test bench under full-friction braking conditions, measuring PM₁₀ and SPN₁₀ emissions. Compliance is demonstrated using brake corner emissions family parents. Conformity of production requires monthly sampling and testing of brake components, with results evaluated using statistical decision charts through 31 December 2029 for PM₁₀ and thereafter for both PM₁₀ and SPN₁₀.

Proposal to amend the scope to allow type approval of vehicles of categories M₁, M₂, N₁ and N₂ with a reference mass not exceeding 2,840 kg at the manufacturer’s request as an extension from vehicles with reference mass not exceeding 2,610 kg, and to allow type approval of special purpose vehicles of categories M₁, M₂, N₁ and N₂ regardless of their reference mass at the manufacturer’s request, with the manufacturer demonstrating to the Type Approval Authority that the vehicle in question is a special purpose vehicle.

Proposal to amend the scope to allow type approval of vehicles of categories M₁, M₂, N₁ and N₂ with a reference mass not exceeding 2,840 kg as direct approvals rather than only as extensions based on approved configurations below 2,610 kg. The modification permits manufacturers to obtain type approval for vehicles within the 2,610 kg to 2,840 kg reference mass range regardless of whether lower-mass configurations of the same vehicle type are approved, addressing concerns that the previous restriction created market distortions affecting different manufacturers differently, a concern heightened by fleet electrification.

Proposal to amend para. 1 to clarify that type approval may be granted to vehicles of categories M₁, M₂, and N₁ with a reference mass not exceeding 2,840 kg at the manufacturer’s request, without requiring an existing approval of a configuration below 2,610 kg. The current wording restricts approval between 2,610 kg and 2,840 kg to extensions of existing approvals, creating market distortion. The concern is becoming more relevant with fleet electrification, as electrified vehicles are heavier and require different type designations in emissions-based regulations.

Proposal to amend para. 3.2.12.2.7.6.3. of Annex 1 to clarify documentation requirements for OBD output codes and data, insert new definitions in Annex 11 for limp-home routines, pending fault code, readiness, confirmed fault code, cold start, and emission control components, amend paras. 3.3.3.5. and 3.3.4.5. to clarify monitoring requirements for emission-related powertrain components, amend para. 3.8.1. to modify fault code erasure criteria, insert new para. 3.8.2. for pending fault code erasure, amend para. 6.5.1. of Appendix I to clarify the meaning of “if available”, amend para. 6.5.3.1. to allow DoIP standards for Pure Electric vehicles from 1 January 2029, amend para. 6.5.3.3.1. to permit SAE J1979-2 and J1979-3 standards, insert new para. 6.5.3.3.2. for DoIP standards, amend para. 7.3.2. to specify when monitor denominators shall be incremented for temperature sensors and boost pressure control systems, and amend para. 1.(e) of Annex 12 to clarify requirements for user-visible active error entries.

Proposal to amend Annex A1 para. 3.2.12.2.7.6.3. to clarify OBD output codes and format documentation requirements, insert new definitions for ‘confirmed fault code’, ‘cold start’, and ‘emission control components’ in para. 3.10.22. to 3.10.24., amend table titles for Tables 4A and 4B in para. 6.8.2. to clarify applicability levels and WLTP phases, amend Annex B5 para. 4.2.2.2. Table A5/1 analytical balance verification criteria, amend Annex C5 para. 3.3.3.5. and 3.3.4.(e) to clarify emission-related powertrain component monitoring requirements, amend para. 3.8.1. to specify fault code erasure conditions based on engine warm-up cycles or driving cycles, insert new para. 3.8.2. for pending fault code erasure, amend Appendix I para. 6.5.1. to clarify ‘if available’ signal usage, amend para. 6.5.3.1. to allow ISO 13400-2 and ISO 13400-4 standards as options from 1 January 2029 for non-pure electric vehicles, and amend para. 7.3.2. regarding denominator increments for temperature sensor and boost pressure control system monitors.

Proposal to amend paragraphs 7.2.1. and 7.2.2. to correct excess exhaust emissions driver warning system requirements, amend Annex 4, Appendix 1, Line 1.50 to add OBM distance since monitoring status reset and OBM current inducement distance parameters, amend Annex 4, Appendix 3, Line 3.7 to add OBM inducement distance and OBM monitoring status reset counter entries, and amend Annex 7, Appendix 1, Table 5 to exclude OVC-HEV from the first row and delete “City” from charge sustaining CO₂ emissions and fuel consumption values for OVC-HEV.

Proposal to amend para. 3.1.2., 12.2.1., 12.2.3., and 12.2.6. to introduce Level 1A, Level 1C, or Level 2 requirements of UN Regulation No. 154 and the 01 series of amendments to UN Regulation No. 168 on real driving emissions. The proposal recognises a new Level for voluntary acceptance by Contracting Parties proposed to be included in UN Regulations Nos. 154 and 168, complementary to proposals to introduce Level 1C in those Regulations.

Proposal to amend the Introduction and para. 1. to provide requirements for four levels of approval including the new Level 1C, modify para. 5.2.1. Section 2 © to include Level 1C in stage/level characters, amend para. 6.2. Table A and para. 6.3.9. to mark OBFCM as not applicable for Level 1C, modify para. 7.4.1., para. 8.1.2. Table 8/1, and para. 8.2.5.1. to exclude Level 1C from OBFCM accuracy requirements, amend para. 3.4. of Appendix 2 and Appendix 5 title to mark OBFCM accuracy and Appendix 5 as not applicable for Level 1C, modify Annexes Part A introductory text and Annex A1 heading row and Appendix 1 Part I table to accommodate Level 1C approval, amend Annex 3 Table A3/1 to add Level 1C code based on European Union, and modify Annex B6 para. 2.6.8.5. to mark OBFCM data recording as not applicable for Level 1C.

Proposal to amend para. 1 to provide requirements for four levels of approval including a new Level 1C based on 4-phase WLTC testing with requirements identical to Level 1A but allowing type approval test substitution with declaration of compliance, amend para. 5.2.1.© to indicate implementing stage/level as 1A, 1B, 1C or 02, amend para. 5.4.3. to require approval mark code distinguishing the level granted, and amend Table A3/1 of Annex 3 to assign code 1C to European Union and code 02 to Harmonized.

Proposal to introduce modifications with regard to the
usage of OBM generated data for the part B In-Service Conformity compliance of the light-duty vehicles’ battery durability, including to amend para. 4. to distinguish verification procedures for vehicles with Over-the-Air data transmission versus other vehicles, amend para. 4.3. to clarify pass/fail criteria and vehicle age counting for battery durability families, and insert new paras. 4.4. to 4.6. to establish manufacturer obligations for On-Board Monitoring systems with Over-the-Air functionality, exemptions from certificate provision and additional dataset requirements, and corrective measures for non-compliant battery durability families.

Proposal to:

• Amend Annex 5, para. 5. and 5.1. to introduce verification of reported assessment of virtual distance,
• Insert new sub-paras. 5.1.1., 5.1.2., 5.1.3., 5.1.4. and 5.1.5. establishing environment temperature requirements, initial State of Charge settings, discharging test procedures, test termination conditions, and verification test methods,
• Amend para. 5.2. to establish pass/fail criteria based on statistical evaluation where verification fails if reported delta virtual distance exceeds measured virtual distance by more than 5 per cent, using a decision chart to determine sample pass or fail outcomes.

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Proposal to:

• Amend para. 3.7.1. to define rated engine power to include system power as per UN Regulation No. 177 if applicable,
• Amend para. 6.3.2.2. to add applicability scope for Level 1A only or 4-phase WLTP test only,
• Amend para. 6.3.2.3. to restructure interpolation family requirements for PEVs with applicability limited to Level 1B or 3-phase WLTP test,
• Amend Annex B1 para. 2.3.2. to exclude PEVs from Class 3 vehicle classification for Level 1B or 3-phase WLTP test,
• Amend Annex B4 para. 6.2.1. to require new vehicle selection upon each change of range and permit re-use of original measurements if vehicle is reselected,
• Amend Annex B4 para. 6.2.4. to establish two-year approval period for wind tunnel facilities with provisions for extension every two years upon manufacturer provision of modification lists and measurement results at three-month intervals,
• Amend Annex B8 para. 1.4. to define vehicle classification and add applicability scope,
• Amend Annex B8 para. 1.4.1.2. to allow use of peak power according to UN Regulation No. 177 for multiple electric machines,
• Amend Annex B8 para. 3.4.1. to add Level 1B applicability for Consecutive cycle Type 1 test procedure selection,
• Amend Annex B8 para. 4.1.2. to remove Level 1B charge-depleting CO₂ emission calculation and clarify 4-phase WLTP test applicability concerning approval of wind tunnel facilities, with reference to GRPE/2026/44.

Proposal to:

• Insert new paragraphs in the introduction to clarify application to vehicles with Automated Driving Systems,
• Add definitions for ADS, ADS road load determination mode, ADS testing mode, and ADS user,
• Amend definitions of mass in running order, powered axle, reference mass, driver user-selectable mode, predominant mode, and configurable start mode to account for vehicles of categories X and Y,
• Amend the On-Board Diagnostic system definition and malfunction indicator definitions,
• Insert footnotes referencing the Consolidated Resolution on the Construction of Vehicles,
• Renumber and amend footnotes regarding Contracting Parties,
• Amend road load family and road load matrix family criteria,
• Amend tables regarding vehicle classifications,
• Amend OBD family definitions,
• Amend reagent warning and reagent inducement system provisions throughout Appendix 6,
• Amend provisions for driver user-selectable modes in Annexes A1 and B6,
• Add special provisions for vehicles of categories X and Y requiring ADS road load determination mode and ADS testing mode in Annexes B4 and B6,
• Amend provisions regarding vehicle operation and testing to reference ADS user in addition to driver,
• Amend provisions in Annexes B8, C3, C4, and C5 to accommodate vehicles equipped with ADS.

Proposal to amend para. 6.1.10. to address division by zero cases when an OVC-HEV consumes zero fuel under charge-depleting conditions by applying good engineering judgement, and amend Annex B8, para. 4.2.2. to modify the charge-depleting fuel efficiency calculation formula for OVC-HEVs and OVC-FCHVs under Level 1B, incorporating treatment of zero fuel consumption cases. The amendments prevent invalid calculations and ensure robustness of WLTP-based methods, addressing limitations in exhaust gas analysis equipment that cause cycle “n” to contain mixed Charge Depleting and Charge Sustaining operation.

Proposal to amend para. 6.1.10. to address division by zero in formulas when an OVC-HEV consumes zero fuel under charge-depleting conditions, and amend Annex B8, para. 4.2.2. to modify the charge-depleting fuel efficiency FECD calculation formula for OVC-HEVs and OVC-FCHVs under Level 1B and 3-phase WLTP testing in Level 2. The amendment applies good engineering judgement optionally to add a dash rather than zero when data input justifiably leads to division by zero.

Proposal to amend para. 4.1. of Appendix 5 to refer to the engine-relevant control unit, amend para. 5.3. to specify that lifetime counter values may be reset only for vehicles whose engine-relevant control unit memory cannot preserve data when unpowered, and amend para. 5.4. to allow counter reset in cases of malfunctioning or engine-relevant control unit replacement. Changes reflect that OBFCM calculation is done in different control units within the vehicle, including battery management for pure electric vehicles.

Proposal to amend para. 6.1.3. of Annex B10 to modify the low temperature pure electric range ratio calculation by allowing the existing PERWLTC,ave value of the representative 23°C interpolation family to be used where multiple low temperature range families belong to the same 23°C family, to avoid additional testing burden while preserving the application of a worst case approach for HVAC systems.

Proposal to add abbreviations for Fourier Transform InfraRed (FTIR) and Quantum Cascade Laser mid-InfraRed detection (QCL-IR) analysers, amend the definition of ‘Type of analyser’ to reference ‘Instrument manufacturer’, insert a new definition of ‘Instrument manufacturer’, amend paragraph 4.1.1 to permit use of QCL-IR or FTIR analysers for gaseous components except THC, add detailed specifications for FTIR and QCL-IR analysers including installation requirements and assessment procedures according to CEN EN 17507:2021, amend paragraph 4.3.5 to add interference check procedures for FTIR and QCL-IR analysers, and insert new Annexes 13 and 14 establishing a protocol for analyser assessment and a model certificate of acceptable analyser assessment.

Proposal to insert a new definition of hydrogen ICE vehicle, amend para. 8.2. to establish a two-step verification procedure for trip dynamic conditions, amend para. 9.3.1. to include requirements for hydrogen-fueled tests, amend para. 9.5. to require validation of software tools for trip verification and emissions calculation, amend para. 10.2. to establish a three-step trip validity assessment procedure, amend Figure 6 to illustrate the trip validity assessment procedure, amend para. 10.6. to include gaseous pollutant and particle number emissions during cold start in normal evaluation for hydrogen-fueled tests, amend para. 10.7. to apply separate data-set creation for 3-phase and 4-phase evaluation, amend Table A4/1 to add engine fuel flow as a test parameter, amend Table A5/1 footnote 3 to make PN concentration mandatory for hydrogen ICE vehicles, insert a new row in Table A7/1 for hydrogen stoichiometric coefficient values, amend Annex 8 title and para. 1. to clarify application to non-hydrogen vehicles, and add new Annex 8a establishing a moving averaging window method using distance-specific work for hydrogen ICE vehicles and amend Annex 11 paras. 2., 3.1., and 3.2. to include work ratio calculations applicable to hydrogen-fueled tests.

Proposal to establish a new UN Regulation transposing UN GTR No. 24 into uniform provisions concerning approval of non-original and identical replacement brake parts (brake pads, drum brake linings, brake discs, and brake drums) with regards to particle emissions. The regulation applies to vehicles of category M₁, N₁, and N₂ between 3.5 and 5 tonnes maximum mass. Replacement brake parts must comply with particle emission limits, with emission factors calculated using test wheel load and friction braking share coefficient for the brake emissions family parent. Approval marks must be affixed to approved parts, and conformity of production shall be verified through sampling and testing procedures.

Proposal to replace para. 9.3.2.8.1. and 9.3.2.9.1. to permit examination and verification of FTIR and QCL-IR analysers by type-approval authorities and designated technical services in addition to metrological institutes, preferably via witnessed testing at the instrument manufacturer’s premises, amend para. 9.3.9.2.2. to permit humidification techniques other than water bubblers and to clarify water concentration requirements for all fuels, and insert new Appendices 10 and 11 setting out a protocol for analyser assessment and a model certificate of acceptable analyser assessment.