Final answer:
Semi-trailers with a width of 80 inches or more are required to have clearance lights, side marker lights, and identification lights to ensure visibility and safety on the road.
Step-by-step explanation:
The required lighting for a semi-trailer that is 80 inches or more in width typically includes various lights to ensure visibility for safety purposes. These generally encompass clearance lights, side marker lights, and identification lights. These lights serve to outline the size and presence of the trailer and are crucial for visibility during nighttime or in poor weather conditions.
Clearance lights are positioned at the widest points of the trailer to show its width, while side marker lights are placed near the front and rear to provide a visual indication of the trailer's length. Identification lights, often a set of three, are mounted on the rear of the trailer, near the top, to assist in identifying the vehicle from behind. It is vital to conform to the specific legal requirements regarding trailer lighting in the jurisdiction where the trailer is operated.