Document ID: chunk:federal_register_of_legislation:F2021C00477:body:0:p51
Version: federal_register_of_legislation:F2021C00477
Segment Type: other
Provision Reference: 
Character Range: 134028–137249

differing coefficients of adhesion (kH and kL), where kH  0.5 and kH / kL  210, the directly controlled wheels must 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 must not be affected and the vehicle must 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 must pass over the boundary between the high- and low-adhesion surfaces and during these tests no part of the outer tyres must cross this boundary7.

Annex 6

Appendix 1

Symbols and definitions
Table:  Symbols and definitions
Symbol                           Notes
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)

H                               the  - value on the high-adhesion surface

L                               the  - value on the low-adhesion surface

F                                force ( N )

Fdyn                             normal reaction of road surface under dynamic conditions with the anti-lock system operative

Fidyn                            Fdyn on axle i in case of power-driven vehicles

Fi                               normal reaction of road surface on axle i under static conditions

FM                               total normal static reaction of road surface on all wheels of power-driven vehicle

FMnd[29]                         total normal static reaction of road surface on the unbraked and non-driven axles of the power-driven vehicle

FMd1                             total normal static reaction of road surface on the unbraked and driven axles of the power-driven vehicle

FWM1                             0.01 FMnd + 0.015 FMd

g                                acceleration due to gravity (9.81 m/s2)

h                                height of centre of gravity specified by the manufacturer and agreed by the Technical Service conducting the approval test

k                                coefficient of adhesion between tyre and road

kf                               k - factor of one front axle

kH                               k