raised line markers on the roadway and shoulder are used to define
Raised pavement marker In the United States, Canada, and Australia, these plastic devices commonly have two angled edges facing drivers and containing one or more corner reflector strips. In areas where snowplowing is frequent, conventional markers are placed in a shallow groove cut in the pavement, or specially designed markers are used which include a protective metal casting that is embedded in recesses in the pavement, allowing the marker to protrude slightly above the pavement surface for increased visibility, much like a cat's eye.[2]