Our friends at ANSI have approved three main classes of clothing regarding visibility: namely, Classes 1, 2, and 3 (surprised?). Actually, there is a class E that’s only for work pants and shorts. When these are worn with Class 2 or 3 garments, they add up to Class 3 coverage.
The higher the class number, the higher the visibility. This is based on the amount of background material (often bright orange, red or green–you want to stand out from your surroundings), the width of the reflective tape, and the photometric performance of the tape (how reflective it is, right?). Except for Class E, all High Visibility clothing must contain 360 degrees of reflective taping around the torso.