Division 2.2.3.4

With the exception of cases according to points 2.2.3.5 and 2.2.3.6, it is necessary for the determination of the braking rate of the towed vehicle to measure the braking rate of the tractor plus the towed vehicle and the thrust on the coupling. The tractor shall meet the requirements laid down in Appendix 1 with regard to the relation between the ratio T_M/F_M and the pressure p_m,

where:

T_M

sum of braking forces at the periphery of all wheels of tractors

F_M

total normal static reaction of road surface on wheels of tractors

p_m

pressure at coupling head of control line

The braking rate of the towed vehicle shall be calculated according to the following formula:

z_R = z_{R + M} + D/F_R

Where:

z_R

braking rate of the towed vehicle

z_{R + M}

braking rate of the tractor plus the towed vehicle

D

thrust on the coupling (tractive force D > 0; compressive force D < 0)

F_R

total normal static reaction of road surface on all wheels of towed vehicle