1. (a) A heavy-duty vehicle is any commercial medium- or heavy-duty on-highway vehicle or a work truck, as defined in 49 U.S.C. 32901(a)(7) and (19). For the purpose of this section, heavy-duty vehicles are divided into four regulatory categories as follows:

   1. (1) Heavy-duty pickup trucks and vans;
   2. (2) Heavy-duty vocational vehicles;
   3. (3) Truck tractors with a GVWR above 26,000 pounds; and
   4. (4) Heavy-duty trailers.
2. (b) The heavy-duty vehicle classification does not include vehicles excluded as specified in 49 CFR 535.3.

[81 FR 74237, Oct. 25, 2016, as amended at 89 FR 52945, June 24, 2024]