CLEPA 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).

Text prepared by the European Association of Automotive Suppliers (CLEPA) and from the International Organization of Motor Vehicle Manufacturers (OICA) to clarify the references to Regulation No. 10 within Regulation Nos. 13 and 13-H.

The use of test reports in Regulation No.13 was first introduced in Annex 11 of UN R13 in 1984. CLEPA proposes this amendment to support the proposal to permit the use of an Annex 19 test report as an alternative method in meeting the vehicle stability function requirements as detailed in Annex 21.

Denmark submitted document GRRF-71-19 (subsequently integrated into GRRF/2012/12) proposing to narrow the compatibility bands for control line pressure versus brake rate. This document challenges the proposed changes as effectively mandating electronic braking and imposing unwarranted costs.

Denmark submitted Document GRRF-71-18 (subsequently integrated into GRRF/2012/12) proposing to narrow the limits for coupling force control systems which are allowed to override the compatibility bands. This document argues against the proposed changes.

Denmark submitted GRRF-71-19 (subsequently in GRRF/2012/12) proposing a new paragraph to require a test point between the coupling head and the trailer relay emergency valve. This document argues that the requirement is already implicit within UN R13 and therefore, that the change is unnecessary.

This document addresses the ramifications of introducing the proposals outlined in GRRF-72-07 (superceded by GRRF-72-07/Rev.1) specifically associated with semi-trailers.

Proposal to clarify the use of test reports in Regulation No.13 as proposed under the Alternative Method for the Evaluation of Electronic Vehicle Stability Control Systems.

CLEPA and OICA proposal to harmonize Regulations Nos. 13 and 13-H with the Federal Motor Vehicle Safety Standard FMVSS 135 on electric vehicle requirements with regard to the regenerative braking system (RBS).

The UN R13 and 13-H include procedures to filter out the effects of electric regenerative braking systems from the braking assessment. This proposal would allow test services to disconnect to RBS prior to running tests. It also would allow the use of DC Ampere-hour meter to measure charge states.

Proposal for collective amendments of amendments to Regulations Nos. 13 (Heavy vehicle braking), 13-H (Brakes of M1 and N1 vehicles), 79 (Steering equipment) and 89 (Speed limitation devices) and the new Regulations on LDWS and AEBS to clarify the references to Regulation No. 10 into the UN Regulations mentioned above.

Correction to ISO reference since Byte 3-4 of EBS 11 is only referenced in Part 2 of ISO 11992 and therefore the text should make explicit that reference along with amendment 1:2007. Also proposes to omit several redundant footnotes and references.

Proposal to clarify approval requirements for vehicles and trailers equipped with anti-lock braking systems with regard to the braking compatibility of towing and towed vehicles, including between ABS and compressed-air braking systems. The proposal revises Annexes 10 and 13 of the regulation.

Proposal to correct typographical errors in Corrigendum 2 to Revision 7 of UN R13 wherein the symbols s, s’ and s_o were erroneously transcribed.

Proposal to remove all references to Annex 10 from Annex 13 by transferring the provisions concerning vehicles with and without anti-lock braking systems to Annex 10.

Proposal to delete the contents of Annex 9 on parking brake systems equipped with a mechanical brake-cylinder locking device due to obsolescence.

Proposal based on informal document GRRF-76-21 to remove all references to Annex 10 from Annex 13 by transferring the provisions concerning vehicles with and without anti-lock braking systems to Annex 10.

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).

Presentation discussing the framework for relating independent regulations on electronic subsystems of braking or steering systems to the primary braking/steering regulations.

CLEPA proposed a framework for relating independent regulations on electronic subsystems of braking or steering systems to the primary braking/steering regulations. This proposal revises the wording, focusing on ESC systems with relation to the requirements for complex electronic control systems under Regulation 13-H.

Proposal to add a maximum supply line pressure of 900kPa when the compressor is at cut-out during testing of electronic braking systems (EBS). The aim is to prevent trailer EBS failure warnings/shut downs when detecting excessive supply line pressure.

UN R13 allows for the exemption of certain vehicles from the requirement for electronic stability controls. This proposal seeks to clarify the scope of the exemptions to include any special purpose vehicle with a non-standard chassis. The change was prompted by a modified vehicle where use of ESC was not feasible, but where the current UN R13 language left doubt as to whether the ESC requirement was applicable.

UN R13 allows for the exemption of certain vehicles from the requirement for electronic stability controls. This proposal seeks to clarify the scope of the exemptions to include any special purpose vehicle with a non-standard chassis. The change was prompted by a modified vehicle where use of ESC was not feasible, but where the current UN R13 language left doubt as to whether the ESC requirement was applicable. This revised proposal takes into account comments received during the February 2016 GRRF session.

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.

UN R13 allows for the exemption of certain vehicles from the requirement for electronic stability controls. This proposal seeks to clarify the scope of the exemptions to include any special purpose vehicle with a non-standard chassis. The change was prompted by a modified vehicle where use of ESC was not feasible, but where the current UN R13 language left doubt as to whether the ESC requirement was applicable. This revised proposal takes into account comments received during the February 2016 GRRF session.

UN R13 allows for the exemption of certain vehicles from the requirement for electronic stability controls. This proposal seeks to clarify the scope of the exemptions to include any special purpose vehicle with a non-standard chassis. The change was prompted by a modified vehicle where use of ESC was not feasible, but where the current UN R13 language left doubt as to whether the ESC requirement was applicable. This revised proposal takes into account comments received during the February 2016 GRRF session.

Proposal to amend provisions on electronic stability control warnings under braking regulations to allow for activation of the ESC visual warning during a stability-assistance intervention of an electronic steering control. The aim is to avoid separate requirements for brake-actuated and steering-actuated stability assistance that would lead to two visual warnings where only one is appropriate.

UN R13 allows for the exemption of certain vehicles from the requirement for electronic stability controls (footnote 12). This proposal (following proposals GRRF/2016/27 and GRRF-82-03) seeks to clarify the scope of the exemptions to include any special purpose vehicle with a non-standard chassis. The change was prompted by a modified vehicle where use of ESC was not feasible, but where the current UN R13 language left doubt as to whether the ESC requirement was applicable.

UN R13 allows for the exemption of certain vehicles from the requirement for electronic stability controls (footnote 12). This proposal (following proposals GRRF/2016/27 as amended by GRRF-82-03 and proposal GRRF-83-31) seeks to clarify the scope of the exemptions to include any special purpose vehicle with a non-standard chassis. The change was prompted by a modified vehicle where use of ESC was not feasible, but where the current UN R13 language left doubt as to whether the ESC requirement was applicable.

Revision 7 of Regulation No. 13 includes a former version of Figure 1B which was changed with Amend 4 to Revision 6 of UN Regulation No. 13. This correction is also needed for Revision 8, which contains the same error.

Discussion presentation for adapting UN R13 to electric vehicle systems with regard to the required state of charge of the vehicle battery under downhill and endurance braking test procedures.

Text submitted by the expert from CLEPA to include state-of-art electro-mechanical braking systems

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

Proposal for amendments to the proposal to introduce provisions for electro-mechanical braking systems (submitted to WP.29 as document WP.29/2021/12).

Comments on the proposal from Germany to require electrically operated parking brake systems to automatically activate when the driver leaves the vehicle cabin and/or the motor is stopped.

Input on the proposal from Germany to require electrically operated parking brake systems to automatically activate when the driver leaves the vehicle cabin and/or the motor is stopped.

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 allow the parking brake warning device to be actuated only once the electric transmission of the parking brake is in a stable state securing the park brake application.

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 introduce provisions for the approval of electromechanical braking systems.

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

Draft proposal to introduce provisions for the type approval of vehicles with electro-mechanical braking (EMB) systems.

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 clarify the application of the proposed changes with regard to electro-mechanical braking.

Proposal to allow a mechanical locking device as an alternative to the friction parking braking to hold the vehicle.

Original proposal as revised during the EBSIG 6th session.

Proposal as updated during the 7th EBSIG session.

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

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 for amendments to the draft provisions on e-trailers.

Proposal to address loss of trailer friction braking efficiency due to increased use of robust endurance braking systems and electrification of trucks. The number of trucks with strong endurance braking systems and increasing electrification of vehicles with more efficient energy recuperating systems reduces the use of friction brakes. As a result, brake pads and linings in some commercial vehicles do not reach a temperature that is needed for the development of optimum brake performance. In particular in trailers, a loss of brake force develops due to brake pads and linings losing effectiveness – they “fall asleep” and need to be replaced although they are not worn out.

Proposal to permit the type approval of a park lock device as an alternative to the friction parking brake(s).

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. 2.2.2.4. 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 amend provisions in documents GRVA/2025/13 and GRVA/2025/14 concerning the type approval of a park lock device as an alternative to or in combination with the friction parking braking.

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

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.

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 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.

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 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.

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.