California Code
ARTICLE 8 - Signs
Section 27902.

27902. Section 27900 does not apply to any motor vehicle having an unladen weight of 6,000 pounds or less or to any vehicle towed by such motor vehicles, or to any motor vehicle operating under manufacturers, dealers, or transporters special plates, or to any motor vehicle operated by a passenger stage corporation subject to the jurisdiction of the Public Utilities Commission.

(Amended by Stats. 1963, Ch. 1021.)