Document ID: chunk:federal_register_of_legislation:F2025C00107:reg:4:p6
Version: federal_register_of_legislation:F2025C00107
Segment Type: reg
Provision Reference: reg 4 (pt 6/26)
Character Range: 101752–104913

limits of the vehicle in maintaining the direction intended by the driver in the case of a power-driven vehicle, and assists in maintaining the direction of the trailer with that of the towing vehicle in the case of a trailer.
     6.                            'Entrance Speed' (of a J-Turn test) means the 0.5 second average of the test vehicle raw speed data, prior to any 'Vehicle Stability Function Service Brake Application', and rounded to the nearest 1.0 km/h.
     7.                            'Initial Brake Temperature' means the average temperature of the service brakes on the hottest 'Axle' of the vehicle immediately before any J-Turn test procedure is executed.
     8.                            'J-Turn Test Course' means a course in accordance with clause 2 of Annex 2 to this appendix.
     9.                            'Lateral Acceleration' means the component of the acceleration vector of a point in the vehicle perpendicular to the vehicle x-axis (longitudinal) and parallel to the road plane.
    10.                       'Oversteer' means a condition in which the vehicle's 'Yaw Rate' is greater than the 'Yaw Rate' that would occur at the vehicle's speed as result of the 'Ackerman Steer Angle'.
    11.                       'Peak Friction Coefficient' or 'PFC' means the ratio of the maximum value of braking test wheel longitudinal force to the simultaneous vertical force occurring prior to wheel lockup, as the braking torque is progressively increased.
    12.                       'Roll-over Control' means a function within a 'Vehicle Stability Function' that reacts to an impending roll-over in order to stabilise the power-driven vehicle or towing vehicle and trailer combination or the trailer during dynamic manoeuvres within the physical limits of the vehicle.
    13.                       'Selective Braking' means a function within a complex electronic control system where actuation of individual brakes is made by automatic means in which vehicle retardation is secondary to vehicle behaviour modification.
    14.                       'Time Zero' means the instant the transverse centreline of the front 'Axle' of the vehicle reaches the start gate (the line within the lane at zero degrees of radius arc angle – see Figure 2 in Annex 1 to this appendix).
    15.                       'Understeer' means a condition in which the vehicle's 'Yaw Rate' is less than the 'Yaw Rate' that would occur at the vehicle's speed as result of the 'Ackerman Steer Angle'.
    16.                       'Vehicle Stability Function' means an electronic control function for a vehicle which improves the dynamic stability of the vehicle.  A 'Vehicle Stability Function' includes one or both of the following:
            1.       'Directional Control';
            2.       'Roll-over Control'.
    17.                       'Vehicle Stability Function Service Brake Application' means the time when the 'Vehicle Stability Function' applies a service brake pressure at any wheel for a continuous duration of at least 0.5 second of at least 34 kPa for pneumatic brake systems and at least 172 kPa for hydraulic brake systems.