The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States.

ANSI classes are a system created by the American National Standards Institute depending on the total area of high-visibility garments. The amount of required visible material increases with each performance class.

CLASS 1: For use by workers who are well separated from traffic and working in areas where vehicle and/or equipment speeds do not exceed 25 mph.

CLASS 2: For workers who are on or near roadways, are exposed to traffic traveling at speeds in excess of 25 mph, and are in situations where complex visual backgrounds may be present.

CLASS 3: For workers in the highest-risk situations, who need to be visible through a full range of body motions from a minimum distance of 1280 feet, and exposed to very high speed traffic.