Utah Code § 41-3-504: Special plates -- Display.

Special plates issued to dealers, dismantlers, manufacturers, remanufacturers, and transporters for the purpose of operating or moving motor vehicles on the highway under the provisions of this chapter shall be:

(1) prominently displayed on the rear of the motor vehicle where clearly visible;

(2) free from foreign materials;

(3) clearly legible; and

(4) securely fastened in a horizontal position.