Division 5.1.2.1 The running resistance for an individual vehicle shall be calculated using the following equation:F1

is the calculated running resistance as a function of vehicle velocity, Nm;

is the constant running resistance coefficient, Nm, defined by the equation:

$c_0=\mathrm{r\prime }∕\mathrm{1,02}\times \mathrm{Max}\left(\left(\mathrm{0,05}\times \mathrm{1,02}\times c_{\mathrm{0r}}∕\mathrm{r\prime }+\mathrm{0,95}\times \left(\mathrm{1,02}\times c_{\mathrm{0r}}∕\mathrm{r\prime }\times \mathrm{TM}∕{\mathrm{TM}}_r+\left(\frac{\mathrm{RR}-{\mathrm{RR}}_r}{1000}\right)\times \mathrm{9,81}\times \mathrm{TM}\right)\right);\left(\mathrm{0,2}\times \mathrm{1,02}\times c_{\mathrm{0r}}∕\mathrm{r\prime }+\mathrm{0,8}\times \left(\mathrm{1,02}\times c_{\mathrm{0r}}∕\mathrm{r\prime }\times \mathrm{TM}∕{\mathrm{TM}}_r+\left(\frac{\mathrm{RR}-{\mathrm{RR}}_r}{1000}\right)\times \mathrm{9,81}\times \mathrm{TM}\right)\right)\right)$

is the constant running resistance coefficient of the representative vehicle of the road load matrix family, Nm;

is the first order road load coefficient, Nm/(km/h), and shall be set to zero;

is the second order running resistance coefficient, Nm/(km/h)², defined by the equation:

c₂ = r′/1,02 × Max((0,05 × 1,02 × c_2r/r′ + 0,95 × 1,02 × c_2r/r′ × A_f/A_fr); (0,2 × 1,02 × c_2r/r′ + 0,8 × 1,02 × c_2r/r′ × A_f/A_fr))

is the second order running resistance coefficient of the representative vehicle of the road load matrix family, N/(km/h)²;

is the vehicle speed, km/h;

is the actual test mass of the individual vehicle of the road load matrix family, kg;

is the test mass of the representative vehicle of the road load matrix family, kg;

is the frontal area of the individual vehicle of the road load matrix family, m²;

is the frontal area of the representative vehicle of the road load matrix family, m²;

is the tyre rolling resistance of the individual vehicle of the road load matrix family, kg/tonne;

is the tyre rolling resistance of the representative vehicle of the road load matrix family, kg/tonne;

is the dynamic radius of the tyre on the chassis dynamometer obtained at 80 km/h, m;

is an approximate coefficient compensating for drivetrain losses.