Ariz. Rev. Stat. § 28-928
The sections of this article, including sections 28-929 through 28-934, relating to clearance and marker lamps, reflectors and stoplights, apply as stated in those sections to vehicles of the type enumerated in the sections, namely passenger buses, trucks, truck tractors and certain trailers, semitrailers and pole trailers, respectively, when operated on a highway. These vehicles shall be equipped as required and all lamp equipment required shall be lighted at the times mentioned in section 28-922, except that clearance and side marker lamps need not be lighted on a vehicle when operated within any municipality where there is sufficient light to render clearly discernible persons and vehicles on the highway at a distance of five hundred feet.
A.R.S. § 28-928