This section describes a methodology for quantifying aerodynamic drag for use in determining input values for tractors as described in § 1037.520 . This coastdown testing is the reference method for aerodynamic measurements.
Where:
CdAcoastdown([PSI]eff) = the average drag area measured during coastdown at an effective yaw angle, [PSI]eff.
CdAalt([PSI]eff) = the average drag area calculated from an alternate drag measurement method at an effective yaw angle, [PSI]eff.
40 C.F.R. §1037.525