Document ID: chunk:federal_register_of_legislation:F2017L01229:body:0:p4
Version: federal_register_of_legislation:F2017L01229
Segment Type: other
Provision Reference: 
Character Range: 11322–14143

for invalid drivers.
  2.  Definitions
 For the purposes of this Regulation,
2.1. "Approval of a vehicle" means the approval of a vehicle type with regard to electronic stability control.
2.2. "Vehicle type" means a category of vehicles which do not differ in such essential respects as:
2.2.1. The manufacturer's trade name or mark;
2.2.2. Vehicle features which significantly influence the performances of the Electronic Stability Control system (e.g. maximum mass, centre of gravity position, track width, distance between axles, tyres dimension and the design of the braking system);
2.2.3. The design of the Electronic Stability Control system.
2.3. "Maximum mass" means the maximum mass stated by the vehicle manufacturer to be technically permissible (this mass may be higher than the "permissible maximum mass" laid down by the national administration).
2.4. "The distribution of mass among the axles" means the distribution of the effect of the gravity on the mass of the vehicle and/or its contents among the axles.
2.5. "Wheel/axle load" means the vertical static reaction (force) of the road surface in the contact area on the wheel/wheels of the axle.
2.6. "Ackerman steer angle" means the angle whose tangent is the wheelbase divided by the radius of the turn at a very low speed.
2.7. "Electronic Stability Control (ESC) System" means a system that has all of the following attributes:
2.7.1. That improves vehicle directional stability by at least having the ability to automatically control individually the braking torques of the left and right wheels on each axle[2] to induce a correcting yaw moment based on the evaluation of actual vehicle behaviour in comparison with a determination of vehicle behaviour demanded by the driver;
2.7.2. That is computer controlled with the computer using a closed-loop algorithm to limit vehicle oversteer and to limit vehicle understeer based on the evaluation of actual vehicle behaviour in comparison with a determination of vehicle behaviour demanded by the driver;
2.7.3. That has a means to determine directly the value of the vehicle's yaw rate and to estimate its side-slip or side-slip derivative with respect to time;
2.7.4. That has a means to monitor driver steering inputs; and
2.7.5. That has an algorithm to determine the need, and a means to modify propulsion torque, as necessary, to assist the driver in maintaining control of the vehicle.
2.8. "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.
2.9. "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 a result of the Ackerman steer angle.
2.10. "Side-slip or side-slip angle" means the