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.
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.
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.
