§ 1037.526 Aerodynamic measurements for trailers.
This section describes a methodology for determining aerodynamic drag area, CdA for use in determining input values for box vans as described in §§ 1037.515 and 1037.520.
(a) A trailer's aerodynamic performance for demonstrating compliance with standards is based on a ΔCdA value relative to a baseline trailer. Determine these ΔCdA values by performing A to B testing, as follows:
(1) Determine a baseline CdA value for a standard tractor pulling a test trailer representing a production configuration; use a 53-foot test trailer to represent long trailers and a 28-foot test trailer to represent short trailers. Repeat this testing with the same tractor and the applicable baseline trailer. For testing long trailers, the baseline trailer is a trailer meeting the specifications for a Phase 1 standard trailer in § 1037.501(g)(1); for testing refrigerated box vans, use a baseline trailer with an installed HVAC unit that properly represents a baseline configuration correlated with the production configuration. For testing short trailers, use a 28-foot baseline trailer with a single axle that meets the same specifications as the Phase 1 standard trailer, except as needed to accommodate the reduced trailer length.