On May 18, the Eighth Circuit held that NHTSA’s informal letters determining that certain aftermarket products violate Federal Motor Vehicle Safety Standard 108 constitute final agency action reviewable under the Administrative Procedure Act (APA). The 2-1 decision reverses the district court’s dismissal and remands for consideration of a preliminary injunction. The holding has implications well beyond the automotive-safety context and shows how the Eighth Circuit evaluates whether informal enforcement correspondence qualifies as final agency action.








