Document ID: chunk:federal_register_of_legislation:F2022C00213:reg:18:p6
Version: federal_register_of_legislation:F2022C00213
Segment Type: reg
Provision Reference: reg 18 (pt 6/6)
Character Range: 154580–156078

and vehicle portions rotating with the wheels during coast down on the road.  Mr should be measured or calculated by an appropriate manner.
         6.1.2.8. The running resistance determined on the track shall be corrected to the reference ambient conditions as follows:

           F corrected = k · F measured

          Where:
                    RR is the rolling resistance at speed V
               RAERO is the  aerodynamic drag at speed V
                    RT is the total road load = RR+RAERO
                    KR is the temperature correction factor of rolling resistance, taken to be equal to:  3.6 x 10-3/C
                    t is the road test ambient temperature in C
                    t0 is the reference ambient temperature = 20 C
                    dt is the air density at the test conditions
                    d0 is the air density at the reference conditions
                     (20 C, 100 kPa) = 1.189 kg/m3.

            The ratios RR/RT and RAERO/RT shall be specified by the vehicle manufacturer on the basis of the data normally available to the company.

           If these values are not available, subject to the agreement of the manufacturer and the technical service concerned, the figures for the rolling/total resistance ratio given by the following formula may be used:

           Where:
            MHP is the test mass
                and for each speed the coefficients a and b are as shown in the following table:

V (km/h)  a            b