In December of 1992, the National Highway Traffic Safety Administration, which regulates the Department of Transportation (DOT), published a new federal law requiring reflective tape on all trailers and semi trucks that are at least 80 inches wide and weigh more than 10,000 pounds. The law is intended to cut down on accidents caused by poor visibility at night and in poor weather. The law also includes positioning requirements.
DOT Approved Tape
There are two types of approved DOT reflective tape. Red and white striped tape, used for the back and bottom of the sides of trailers, must be two inches wide. The second type is white or silver reflective tape, used for the top of the truck's back end. While there are many types of reflective tape, the tape meeting DOT requirements must have "DOT C2" on the label.
Trailers that are rectangular must have red and white along the entire bottom of the back of the trailer and the entire lower rear bar as well. They also must have red and white on the bottom of both sides from front to back. This can be broken up into even segments, but tape must cover at least 50 percent of the total side length.
Top of Rectangular Trailers
Rectangle trailers must also have white or silver tape along the top corners in the back, forming an L shape, and each strip must be at least 12 inches long. The silver tape is not required along the top of the sides for a rectangular trailer.
Circular trailers used to carry gas or other liquid material have the same tape requirements along the bottom of the back as well as the sides. Due to the circular top, though, the white or silver tape must be placed at the highest outer portion of the top.
Trucks Without Trailers
For trucks that lack trailers but still meet the width or weight limits, reflective tape is required. The red and white tape must cover the entire length above both mud flaps. The silver or white should be placed on the top corners of the back of the truck in an L shape, as required on the trailers.