Document ID: chunk:federal_register_of_legislation:F2021C01192:body:0:p47
Version: federal_register_of_legislation:F2021C01192
Segment Type: other
Provision Reference: 
Character Range: 124805–127488

system fully cycling on the high-adhesion surface, the passage from one surface to the other is made at high and at low speed, under the conditions laid down in paragraph 5.3.1.;9
5.3.3.  When a vehicle passes from a low-adhesion surface (kL) to a high-adhesion surface (kH) where kH  0.5 and kH / kL  2,10 with the full force8 applied on the control device, the deceleration of the vehicle shall rise to the appropriate high value within a reasonable time and the vehicle shall not deviate from its initial course. The running speed and the instant of applying the brake shall be so calculated that, with the anti-lock system fully cycling on the low-adhesion surface, the passage from one surface to the other occurs at approximately 50 km/h;
5.3.4.  The provisions of this paragraph shall only apply to vehicles equipped with anti-lock systems of categories 1 or 2. When the right and left wheels of the vehicle are situated on surfaces with differing coefficients of adhesion (kH and kL), where kH  0.5 and kH / kL  2,10 the directly controlled wheels shall not lock when the full force 8/ is suddenly applied on the control device at a speed of 50 km/h;
5.3.5.  Furthermore, laden vehicles equipped with anti-lock systems of category 1 shall, under the conditions of paragraph 5.3.4. of this annex satisfy the prescribed braking rate in Appendix 3 to this annex;

5.3.6.  However, in the tests provided in paragraphs 5.3.1., 5.3.2., 5.3.3., 5.3.4. and 5.3.5. of this annex, brief periods of wheel-locking shall be allowed. Furthermore, wheel-locking is permitted when the vehicle speed is less than 15 km/h; likewise, locking of indirectly controlled wheels is permitted at any speed, but stability and steerability shall not be affected and the vehicle shall not exceed a yaw angle of 15° or deviate from a 3.5 m wide lane;
5.3.7.  During the tests provided in paragraphs 5.3.4. and 5.3.5. of this annex, steering correction is permitted, if the angular rotation of the steering control is within 120° during the initial 2 seconds, and not more than 240° in all. Furthermore, at the beginning of these tests the longitudinal median plane of the vehicle shall pass over the boundary between the high- and low-adhesion surfaces and during these tests no part of the outer tyres shall cross this boundary.7
Annex 6 - Appendix 1
  Symbols and definitions
Symbol     Definitions
E          wheelbase

          the adhesion utilized of the vehicle:  quotient of the maximum braking rate with the anti-lock system operative (zAL) and the coefficient of adhesion (k)

i         the  - value measured on axle i (in the case of a motor vehicle with a category 3 anti-lock system)