Text prepared by the United Kingdom of Great Britain and Northern Ireland to review and simplify the UN R 13-H transitional provisions.

In the framework of the International Whole Vehicle Type Approval (IWVTA) discussion, it was agreed to split Regulation No. 13-H into three distinct Regulations: on Braking, on Brake Assist Systems (BAS) and on Electronic Stability Control (ESC). In order to complete this task and to ease the implementation work of Contracting Parties relying on the existing text of the Regulation to mandate BAS or ESC, new transitional provisions are proposed.

Proposal for revised transitional provisions under the regulation.

Proposal to establish an expert group to develop amendments to UN R13 and R13-H that would permit the introduction of braking systems using electric control transmission and electric energy transmission.

Proposal to align the regulation with technical advances and the emergence of a new type of braking system that employs stored electrical energy for both the control transmission and the energy transmission. The proposal would also amend the requirements for the safety of electronic systems.

Proposal as updated during the 7th EBSIG session.

UN R13 and UN R78 establish different brake system requirements for 4-wheel vehicles. R13H requires split service brake systems with front/rear proportioning; R78 permits split service brake systems, combined brake systems, or two separate service brake systems without proportioning requirements. Type-O dry braking tests differ: R13H requires engine disconnected at 100 km/h with stopping distance 0.1v + 0.0060 v² and MFDD 6.43 m/s²; R78 specifies multiple tests at 40, 60, and 100 km/h with varying requirements. Type-I brake fade tests use different snub protocols and performance thresholds. Secondary braking failure criteria differ at specified speeds. R78 requires wet brake testing, a 30 km/h dynamic park brake test with 18% gradient and 5 minutes hold time; R13H specifies static gradient tests. R78 includes detailed ABS, functional safety, and regenerative braking requirements; R13H does not.

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.

Proposal to amend Annex 8, para. 3.4.1. to require that the strategy chosen shall not prejudice safe operation of the system due to failures with other systems involved in achieving the function of the system, and amend Annex 8, para. 3.4.4. to require that analysis of system behaviour on fault occurrence includes faults with other systems involved in achieving the function of the system, and to correct ‘safetys’ to ‘safety’. The proposal addresses a collision where tyre failure resulted in unsafe ABS activation. Although the 02 series clarified ABS as part of electronic control systems assessment, it does not explicitly state what is covered, potentially missing relevant faults or failures influencing system function. The additions ensure all relevant faults or failures are accounted for in manufacturers’ safety concept and analysis.