VEH § 667

(a) A “utility trailer” is a trailer or semitrailer used solely for the transportation of the user’s personal property, not in commerce, which does not exceed a gross weight of 10,000 pounds or a manufacturer’s gross vehicle weight rating of 10,000 pounds.

(b) Notwithstanding subdivision (a), a “utility trailer” includes a trailer or semitrailer designed and used for the transportation of livestock, not in commerce, which does not exceed a gross weight of 10,000 pounds or a manufacturer’s gross vehicle weight rating of 10,000 pounds.