Retroreflective sheeting for road signs is categorized by construction and performance specified by technical standards such as ASTM D4956-11a,; various types give differing levels of retroreflection, effective view angles, and lifespan. Sheeting has replaced button copy as the predominant type of retroreflector used in roadway signs.
There are several grades of retroreflective sheeting which include the three major grades: engineer grade, high intensity prismatic (HIP) and diamond grade. Within these categories are further delineations based on material used and visibility distance. Diamond grade typically has the greatest distance for visibility of the three major categories.