# Commission Delegated Regulation (EU) 2015/68 of 15 October 2014 supplementing Regulation (EU) No 167/2013 of the European Parliament and of the Council with regard to vehicle braking requirements for the approval of agricultural and forestry vehicles (Text with EEA relevance), Appendix 1

Extent: E+W+S+N.I.

Symbols
The following symbols are used in Appendices 2, 3 and 4:
FMnd and FMd in case of two-axled power-driven vehicles: these symbols may be simplified to corresponding Fi-symbols.
Symbol
Notes
E
wheelbase
ER
distance between coupling point and centre of axle(s) of rigid drawbar towed vehicle (or distance between coupling point and centre of axle(s) of centre-axle towed vehicle)
ε
the adhesion utilised by the vehicle: quotient of the maximum braking rate with the anti-lock braking system operative (zAL) and the coefficient of adhesion (k)
εi
the ε-value measured on axle i (in the case of a tractor with a category 3 anti-lock braking system)
εΗ
the ε-value on the high-friction surface
εL
the ε-value on the low-friction surface
F
force [N]
FbR
braking force of the towed vehicle with the anti-lock braking system inoperative
FbRmax
maximum value of FbR
FbRmaxi
value of FbRmax with only axle i of the towed vehicle braked
FbRAL
braking force of the towed vehicle with the anti-lock braking system operative
FCnd
total normal reaction of road surface on the un-braked and non-driven axles of the vehicle combination under static conditions
FCd
total normal reaction of road surface on the un-braked and driven axles of the vehicle combination under static conditions
Fdyn
normal reaction of road under dynamic conditions with the anti-lock braking system operative
Fidyn
Fdyn on axle i in case of tractors or drawbar towed vehicle
Fi
normal reaction of road surface on axle i under static conditions
FM
total normal static reaction of road surface on all wheels of the tractor
FMnd
total normal static reaction of road surface on the un-braked and non-driven axles of the tractor
FMd
total normal static reaction of road surface on the un-braked and driven axles of the power-driven vehicle
FR
total normal static reaction of road surface on all wheels of towed vehicle
FRdyn
total normal dynamic reaction of road surface on the axle(s) of rigid drawbar towed vehicle or centre-axle towed vehicle
FwM
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
hD
height of drawbar (hinge point on towed vehicle)
hK
height of fifth wheel coupling (king pin)
hR
height of centre of gravity of the towed vehicle
k
coefficient of adhesion between tyre and road
kf
k-factor of one front axle
kH
k-value determined on the high-friction surface
ki
k-value determined on axle i for a vehicle with a category 3 anti-lock braking system
kL
k-value determined on the low-friction surface
klock
value of adhesion for 100 % slip
kM
k-factor of the tractor
kpeak
maximum value of the curve ‘adhesion versus slip’
kr
k-factor of one rear axle
kR
k-factor of the towed vehicle
P
mass of individual vehicle [kg]
R
ratio of kpeak to klock
t
time interval [s]
tm
mean value of t
tmin
minimum value of t
z
braking rate [m/s2]
zAL
braking rate z of the vehicle with the anti-lock braking system operative
zC
braking rate z of the vehicle combination, with the towed vehicle only braked and the anti-lock braking system inoperative
zCAL
braking rate z of the vehicle combination, with the towed vehicle only braked and the anti-lock braking system operative
zCmax
maximum value of zC
zCmaxi
maximum value of zC, with only axle i of the towed vehicle braked
zm
mean braking rate
zmax
maximum value of z
zMALS
zAL of the tractor on a ‘split surface’
zR
braking rate z of the towed vehicle with the anti-lock braking system inoperative
zRAL
zAL of the towed vehicle obtained by braking all the axles, the tractor un-braked and its engine disconnected
zRALH
zRAL on the surface with the high coefficient of adhesion
zRALL
zRAL on the surface with the low coefficient of adhesion
zRALS
zRAL on the split surface
zRH
zR on the surface with the high coefficient of adhesion
zRL
zR on the surface with the low coefficient of adhesion
zRHmax
maximum value of zRH
zRLmax
maximum value of zRL
zRmax
maximum value of zR

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Source: https://www.legislation.gov.uk/eur/2015/68/annex/XI/appendix/1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2015-68/annex-XI/appendix-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.