California Code, Vehicle Code - VEH § 2436.3

(a) On and after July 1, 1992, every employer shall obtain from the department a carrier identification number.  Application for a carrier identification number shall be on forms furnished by the department.  The number shall be displayed on both sides of each tow truck utilized in any freeway service patrol operation, in accordance with Section 27907.

(b) No employer shall operate a tow truck in any freeway service patrol operation if the carrier identification number issued pursuant to subdivision (a) has been suspended by the commissioner pursuant to Section 2432.1.

(c) The carrier identification number shall be removed before sale, transfer, or other disposal of the vehicle, or upon termination of an agreement or contract for freeway service patrol operations.

(d) A violation of this section is a misdemeanor.