various colors driver warning road reflective stud raised pavement marker

A raised pavement marker is a safety device used on roads. These devices are usually made with plastic, or occasionally metal, and come in a variety of shapes and colors. Raised reflective markers, such as plastic, metal ones, include a lens or sheeting that enhances their visibility by retroreflecting automotive headlights, Some other names for specific types of raised pavement markers include delineators, cat's eyes, road studs, or road turtles. Sometimes they are simply referred to as "reflectors".