40 CFR § 1037.211 - Preliminary approval for manufacturers of aerodynamic devices.
(a) If you design or manufacture aerodynamic devices for trailers, you may ask us to provide preliminary approval for the measured performance of your devices. While decisions made under this section are considered to be preliminary approval, we will not reverse a decision where we have given you preliminary approval, unless we find new information supporting a different decision. For example, where we measure the performance of your device after giving you preliminary approval and its measured performance is less than your data indicated, we may rescind the preliminary approval of your test results.
(b) To request this, you must provide test data for ΔCdA values as specified in § 1037.150(u) or § 1037.526. Trailer manufacturers may use approved ΔCdA values as inputs under § 1037.515 to support their application for certification.