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 amend Annex 8, para. 3.4.1. to require the vehicle manufacturer to supplement its statement with an explanation of how the chosen strategy ensures system objectives do not prejudice safe operation of systems referred to and a description of the validation plan, and to require the designated technical service to perform an assessment of the manufacturer’s explanation and validation plan suitability and may perform or require tests as specified in para. 4., and amend Annex 8, para. 3.4.4. to require documentation supported by analysis showing system behaviour on fault occurrence including faults with other systems involved in achieving system function, to establish and maintain analytical approaches open for inspection by the designated technical service at type approval, and to require the designated technical service to perform assessment including inspection of safety approach at concept and system levels and validation plans and results.

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.

In January 2022, an M₁ passenger vehicle with a detached tyre caused its Anti-lock Braking System to activate, preventing effective braking and resulting in collision with a stationary lorry. The coroner concluded the ABS functioned as intended but created an unsafe scenario by using the fastest rotating wheel as reference speed, and recommended changes to prevent future deaths. The UK proposal to amend UN R13-H would require manufacturers to affirm that strategies to achieve system objectives will not prejudice safe operation of systems under non-fault conditions, including failures of other systems involved in achieving system function such as tyres or wheels, and that documentation be supported by analysis showing how the system will behave upon any fault with bearing on vehicle control, performance, or safety, including faults with other systems involved in achieving system function.

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.