is the arithmetic mean of the peak braking force coefficients of the candidate tyre Tn within a braking test; Δμpeak(R)=μpeak,adj(R)−μpeak(R0)

μpeak,adj(R) is the adjusted peak braking force coefficient in accordance with Table 3;

μpeak(R0) = 0.85 is fixed as the peak braking force coefficient for the reference tyre in the reference conditions; Δϑ=ϑ−ϑ0

ϑ is the measured wet surface temperature in degrees Celsius when the candidate tyre Tn is tested;

ϑ0 is the wetted surface reference temperature for the candidate tyre according to its sidewall marking as listed in Table 4;

ΔMTD=MTD−MTD0

MTD is the measured macro texture depth of the track

MTD0 = 0.8 mm is fixed as the macro texture depth of the reference track;

Ktrailer = 1.50 is a factor to grant consistency between previous calculation of the wet grip index and this one, and to ensure convergence between vehicle and trailer method and

coefficient a, b, c and d are given in Table 4.

 a5c0