19 CFR 112.27 - Marking of vehicles and vessels.
(a) Marking required. Every vehicle licensed by Customs for cartage and every barge, scow, or other lighter licensed by Customs for lighterage shall be marked with the legend “Customhouse License No. ____”, and the name of the person or firm to whom the license has been issued. The abbreviated legend “C.H.L. No. ____” may be used.
(b) Size of marking. The marking required by this section shall appear in letters and figures not less than 3 inches high.
(c) Place of marking -
(1) Carts, trucks, drays, and other vehicles. Every cart, truck, dray, or other vehicle used for Customs cartage by a licensed cartman shall be marked with the required legend and name on each side by painting directly onto the vehicle, or by the permanent attachment of signs bearing the required marking. However, if such marking is found by the port director to be impractical, he may designate some other conspicuous place upon the vehicle where the marking shall appear.
(2) Barges, scows, lighters, and other vessels. Every barge, scow, lighter, or other vessel used for Customs lighterage by a licensed lighterman shall be conspicuously marked with the required legend and name.
(d) Removal of marking upon termination of license. The markings required by this section shall be removed upon termination of the license.