49 CFR 585.142: Scope.

This subpart establishes requirements for manufacturers of passenger cars, multipurpose passenger vehicles, trucks, and buses with a GVWR of 3,855 kg (8,500 pounds) or less and an unloaded vehicle weight of 2,495 kg (5,500 pounds) or less, except for walk-in van-type trucks or vehicles designed to be sold exclusively to the U.S. Postal Service, to submit a report per § 585.147, and maintain records related to the report according to § 585.148, concerning the number of such vehicles that meet the requirements of part 563, Event data recorders (49 CFR 563).