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.

Presentation on electrically propelled and recuperating trailers. The document outlines communication flows between towing vehicles and e-trailers using ISO 11992-2 over ISO 7638-1, involving parameter groups EBS14 (control), EBS28 (energy/state of charge), and EBS29 (status). Key principles include the towing vehicle setting control modes and requesting torque, with trailers reporting capabilities. The document discusses support for maximum three e-axle equipped trailers due to bandwidth limitations, enabling of e-trailer control via CANopen Service Data Objects, and backward compatibility with ISO 11992-2:2014. Amendments to UN Regulation 13 are planned with target entry into force in May 2028.

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:

1. Enable real-time reading of electrical transmission brake demand values via an OBD connector and scan tool during periodical technical inspections,
2. Clarify that only one braking control (e.g., service braking control, parking brake control) shall be used for each test condition of the secondary braking effectiveness and to permit the selection of the braking control based on the vehicle load condition,
3. 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 to:

1. Clarify that only one braking control (e.g., service braking control, parking brake control) shall be used for each test condition of the secondary braking effectiveness and permit the selection of the braking control based on the vehicle load condition, and
2. Establish definitions for “e-axle”, “e-axle trailer” and “dynamo function” and provisions for the approval of e-axle trailers with regard to their “dynamo function”.

Proposal to:

1. Clarify that only one braking control (e.g., service braking control, parking brake control) shall be used for each test condition of the secondary braking effectiveness and permit the selection of the braking control based on the vehicle load condition, and
2. Establish definitions for “e-axle”, “e-axle trailer” and “dynamo function” and provisions for the approval of e-axle trailers with regard to their “dynamo function”.

Proposal to

1. Enable real-time reading of electrical transmission brake demand values via an OBD connector and scan tool during periodical technical inspections,
2. Clarify that only one braking control (e.g., service braking control, parking brake control) shall be used for each test condition of the secondary braking effectiveness and to permit the selection of the braking control based on the vehicle load condition, and
3. 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”.

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 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 amend para. 2.2.2.4. to include electric regenerative braking system and electric propulsion system, amend para. 2.21. to define Electric Regenerative Braking (ERB), add para. 2.56. to define e-trailer, amend para. 5.2.2.7. regarding braking surface connection and electrical regenerative braking system disconnection, insert para. 5.2.2.26. establishing special requirements for e-trailers and trailers equipped with ERB of Category O₃ or O₄, insert Annex 4 paras. 1.7.1.3., 3.1.2.6., and 3.1.3.5. requiring ERB system deactivation during brake applications and tests, insert Annex 13 para. 4.7. requiring anti-lock braking system for vehicles with ERB, and amend Annex 16 tables to include trailer regenerative system parameters, based on GRVA/2025/15.

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