Proposal to clarify that the use of any braking system control for testing the effectiveness of the secondary braking system in failure conditions is allowed.

Proposal to add definitions for “e-axle”, “e-axle trailer”, and “dynamo function” for trailers of category O₃ and O₄, amend paragraph 2.2.2.4. to reference electric regenerative braking systems and electric propulsion systems, insert new paragraphs 5.2.2.26.1. through 5.2.2.26.5. establishing special requirements for dynamo function including maximum retardation power of 20kW, wheel locking prevention at speeds above 15 km/h, and assessment according to Annex 18, insert requirements in Annex 4 to switch off electric regenerative braking systems and dynamo function during brake applications and tests, and amend Annex 19 Appendices 5 and 7 to include e-Axles in schematic diagram considerations. This document is based on GRVA/2025/15 and GRVA-21-12.

Proposal to establish definitions for “e-axle”, “e-axle trailer” and “dynamo function” and to establish provisions for the approval of e-axle trailers with regard to their “dynamo function”.

Proposal from OICA, CLEPA, and CITA to amend CITA’s proposal to enable real-time reading of electrical transmission brake demand values via an electronic vehicle interface and an off-board electronic device during periodical technical inspections, including a 24-month transitional period.

This document proposes amendments to UN Regulation 13 for trailers with dynamo function, superseding GRVA-22-26, GRVA-2025-15, and GRVA-21-12. The dynamo function converts vehicle kinetic energy into electrical energy without affecting braking system forces and is limited to trailers of category O₂, O₃, and O₄ pending further development. Maximum retardation power limits are 22 kW for O₃/O₄ trailers and 2 kW for O₂ trailers, measured using specified methods. Requirements include wheel locking prevention with braking rate not exceeding 0.04 per wheel, functional safety assessment per Annex 18, and demonstration that anti-lock and stability control systems comply when dynamo function is enabled. The dynamo function shall not be used during brake application testing. Administrative amendments update Annexes 2, 4, 5, 10, 19, 20, and 21 to reference e-axles and dynamo functions.

Proposal to clarify that the parking brake may be actuated while the vehicle is in motion via actuation of the vehicle’s service braking system by means of an auxiliary control which could be an Electronic Parking Brake (EPB) and to promote consistent interpretation of the activation conditions for an Emergency Stop Signal (ESS), including by application of the service braking system via the EPB control.

The e-Trailer Industry Group reports on discussions regarding electrically propelled and recuperating trailers. ISO 11992-2 Edition 4 is not safely implementable due to incompatibility with current UN regulations, missing PGNs, and risks of malfunction. ISO/TC 22/SC 31/WG 4 launched Edition 5, targeting publication in early 2027. Amendments to UN R13 and UN R100 are being developed in phases, with Phase 1 addressing trailer dynamo function and Phase 2 addressing e-axle trailers. Two workshops with Contracting Parties are planned to establish shared understanding and develop concrete parameter extensions for amending UN Regulations.

Proposal to amend para. 2.8 of Annex 8 to add subparagraph (c). The amendment addresses trailers utilizing service braking system energy reserves for automatic brake requirements. Current para. 2.8 includes options (a) and (b) requiring spring brake pressure reduction or corresponding pressure reduction in spring compression chamber. New subparagraph (c) permits alternative designs where combined service braking and parking braking system activation holds a laden trailer on 18 percent gradients at any service brake energy reservoir pressure from 850 kPa to 0 kPa, providing greater realization flexibility while maintaining required holding performance.

Proposal to amend para. 2.8 of Annex 8 to UN R13 to require trailers utilizing service braking system energy reserves to fulfil one of three requirements when uncoupled and park brake control released: pressure in spring brake compression chamber shall reduce to 0 kPa when energy reserves reduce to 280 kPa, pressure reduction in service braking system energy reserve results in corresponding reduction in spring compression chamber pressure, or combined service and parking braking forces shall hold laden trailer as required when service brake energy reservoir reduces from 850 kPa to 0 kPa.

Proposal to delete paragraph 1.2.6. excluding e-axle trailers with e-axles providing electric propulsion and/or incorporating an electric regenerative braking system from the scope of UN R13, and add definitions of “e-axle,” “e-axle trailer,” “dynamo function,” and “e-trailer”; add special requirements for power-driven vehicles supporting e-trailer operation, e-axle trailers equipped with dynamo function, and e-trailers of category O; add requirements for electric control lines conforming to ISO 11992-2:²⁰²⁷; specify message support and functional compatibility; and add provisions for electric regenerative braking, dynamo function, and propulsion, including parameters such as retarder torque demand priority, propulsion force limits, overriding mode activation at speeds below 15km/h, and vehicle stability function interaction.

Correlation table showing the corresponding provisions of the current versions of UN R13 and UN R13-H as far as they are related to the proposed amended provisions by the EMB Informal Group regarding electro-mechanical braking systems.

Proposal to introduce requirements for the type approval of Electro-Mechanical Braking (EMB) systems.

Proposal by the expert from the European Association of Automotive Suppliers (CLEPA) to include provisions for the type approval of Electro-Mechanical Braking (EMB) systems as state-of-the-art braking systems. This document supersedes ECE/TRANS/WP.29/GRVA/2021/24.

Proposal to resolve problems with installation of stronger spring brake actuators in trailers to realize higher deceleration in the case of emergency braking caused by a cut of the supply line between towing vehicle and trailer.

Proposal to clarify provisions regarding the actuation of the parking brake warning device to cover the case of electric control transmission systems where there may be a transition between parked (applied) and un-parked (released) braking states. The aim is to reduce risks of user confusion by specifying that the warning device would be actuated only after the parking brake has achieved a stable applied state.

Proposal to permit the use of a positive lock type system as an alternative to a friction type parking brake system.

Proposal to clarify provisions concerning the type-IIA test and the test mass of vehicles authorized to tow trailer(s) (responding to the proposal made in document GRVA/2024/7).

Proposal for provisions to enable the use of approval of a park lock device as an alternative to the friction parking braking to hold the vehicle.

Proposal to enable the type approval of a park lock device as an alternative to, or in combination with the friction parking braking to hold the vehicle.

Proposal to introduce provisions for the approval braking systems for e-trailers and Electric Regenerative Braking (ERB) in towed vehicles of Category O.

Proposal to resolve the problem of decreasing trailer brake performance caused by brake pads and linings “falling asleep”.

Proposal to amend para. 2.8 of Annex 8 to add a new requirement that braking forces from combined service and parking braking systems shall hold a laden trailer as required in Annex 4 para. 3.2.1 at any time when service brake energy reservoir pressure reduces from 850 kPa to 0 kPa, ensuring continuous trailer immobilisation during service brake pressure depletion while establishing a performance-based requirement rather than prescribing specific technical solutions.

Copy of a 2009 draft proposal to amend Regulation No. 13 to specify uniform requirements for towing trailers and motor vehicles which may tow more than one trailer (road train combinations).

Proposal to require the installation of a message routing function (per ISO 11992) on trailers that are:

• equipped with more than one brake electronic control unit,
• equipped with an electric control, and
• towing a trailer.

Proposed changes to align RxSWIN provisions with the RxSWIN template adopted through WP.29-197-06, remove the proposed requirement to comply with UN R156/01 or later from R157 and R171, remove amendments to UN R155 as decided by the IWG CS/OTA, apply the RxSWIN amendments also to earlier series of amendments in R13, R13-H, R79, R131, R152, R157, and R171, update references to the latest version of R.E.3, ECE/TRANS/WP.29/78/Rev.8, in earlier series, and correct paragraph references and improve structure in R89, R139, R140, R155, R156, and R171.