What is required on the rear of every trailer that is 80 inches or more in width?

For trailers that are 80 inches or more in width, it is required to have two red tail-lamps on each side. This regulation is in place to ensure visibility and safety on the road. The red tail lamps are crucial because they indicate to other drivers the presence and width of the trailer, especially in low-light conditions or at night. Such visibility helps in preventing accidents by giving adequate notice to other road users about the dimensions and movements of the trailer.

Amber clearance lamps, while important for signaling the presence of wider vehicles, are typically placed at the front and sides of the trailers to indicate its width at the front. Green reflectors are not standard requirements, and there would be notable regulations that exclude the idea of having 'no requirements' for such trailers due to safety concerns. Therefore, the presence of the red tail-lamps is essential to meet compliance with safety regulations and to ensure that the vehicle is clearly seen by other drivers.