Document ID: chunk:federal_register_of_legislation:F2021C00476:body:0:p50
Version: federal_register_of_legislation:F2021C00476
Segment Type: other
Provision Reference: 
Character Range: 138738–142098

limit of wear, and higher values up to 0.4 may be used at the discretion of the Technical Service.  The actual value obtained and the type of tyres and surface shall be recorded.

7/ Until a uniform test procedure is established, the tests required by this paragraph may have to be repeated for vehicles equipped with electrical regenerative braking systems, in order to determine the effect of different braking distribution values provided by automatic functions on the vehicle.

8/ "Full force" means the maximum force laid down in Annex 3 to this Regulation; a higher force may be used if required to activate the anti-lock system.

9/ The purpose of these tests is to check that the wheels do not lock and that the vehicle remains stable; it is not necessary, therefore, to make complete stops and bring the vehicle to a halt on the low-adhesion surface.

       10/ kH is the high-adhesion surface coefficient
        kL is the low-adhesion surface coefficient
        kH and kL are measured as laid down in Appendix 2 to this annex.

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

FMd  1/                          total normal static reaction of road surface on the unbraked and driven axles of the power-driven vehicle

FWM  1/                          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

TABLE:  SYMBOLS AND DEFINITIONS  (cont'd)

SYMBOL                                     NOTES

kH                                         k - value determined on the high-adhesion surface

ki                                         k - value determined on axle i for a vehicle with a category 3 anti-lock system

kL                                         k - value determined on the low-adhesion surface

klock                                      value of adhesion for 100 per cent slip

kM