Document ID: chunk:federal_register_of_legislation:F2025C00113:reg:4:p5
Version: federal_register_of_legislation:F2025C00113
Segment Type: reg
Provision Reference: reg 4 (pt 5/10)
Character Range: 82962–86316

A 'Vehicle Stability Function' includes one or both of the following:
(a) 'Directional Control';
(b) 'Roll-over Control'.

 1.                                  Functional requirements
     1.                            For each category TD trailer required to be equipped with a 'Vehicle Stability Function' as defined above, the following shall apply:
         1.                     In the case of 'Directional Control', the function must have the ability to automatically control individually the speed of the left and right wheels on each 'Axle' or an 'Axle' of each 'Axle Group' by 'Selective Braking' based on the evaluation of actual trailer behaviour in comparison with a determination of the relative behaviour of the towing vehicle.
         2.                     In the case of 'Roll-over Control', the function must have the ability to automatically control the wheel speeds on at least two wheels of each 'Axle' or 'Axle Group' by 'Selective Braking' or 'Automatically Commanded Braking' based on the evaluation of actual trailer behaviour that may lead to roll-over.
     2.                            To realise the functionality defined above a 'Vehicle Stability Function' must include, in addition to 'Automatically Commanded Braking' and where appropriate 'Selective Braking', at least the following:
         1.                     The determination of actual trailer behaviour from values of the vertical force on the tyre(s), or at least lateral acceleration and wheel speeds.  Only on-board generated information may be used.  If these values are not directly measured, the 'Manufacturer' must supply to the 'Administrator' sufficient evidence of the appropriate correlation with directly measured values under all driving conditions (e.g. including driving in a tunnel).
     3.                            The 'Vehicle Stability Function', including the 'Roll-over Control' function, does not need to be operational during system initialisation, at trailer operating speeds below 20 km/h, when the trailer is being reversed, or if disabled by an operator according to clause 2.3.1 below.
         1.                     A separate and distinct means (for example an off road mode selector/switch on the trailer) may be provided to enable an operator to disable the 'Vehicle Stability Function' for trailer operating speeds up to 40 km/h.
     4.                            Trailers equipped with an electric 'Control Line' must, when electrically connected to a towing vehicle with an electric 'Control Line', provide the information "VDC active" via the data communications part of the electric 'Control Line' when the 'Vehicle Stability Function' is in an intervention mode.  Interventions of the 'Vehicle Stability Function' used in any learning process to determine the trailer operational characteristics must not generate the above information (note: VDC or Vehicle Dynamic Control, as defined within ISO 11992‑2:2003 including Amd.1:2007, is defined within this national standard as a 'Vehicle Stability Function').

APPENDIX 4

 Electrical requirements for all trailers (over 4.5 tonnes 'ATM') incorporating an electric 'Control Line', an 'Antilock System', or a 'Vehicle Stability Function'

 1.                                  Electrical supply system requirements
     1.                            Each trailer must