<P> A raised pavement marker is a safety device used on roads . These devices are usually made with plastic, ceramic, thermoplastic paint or occasionally metal, and come in a variety of shapes and colors . Raised reflective markers include a lens or sheeting that enhances their visibility by retroreflecting automotive headlights . Some other names for specific types of raised pavement markers include convex vibration lines, Botts' dots, delineators, cat's eyes, road studs, or road turtles . Sometimes they are simply referred to as "reflectors". </P> <P> The surface of this type of vibrating coating line is distributed and scattered with raised bumps . Some bumps are coated with high - refractive - index glass beads . When a speeding vehicle runs over the raised road lines, it produces a strong warning vibration to remind the car driver of deviation from the lane . Perpendicular to driving directions, these marking lines are used for settled mainline toll plaza, ramp entrances, mountainous areas, continuous sharp turns, downhill sections and the end of the highway (intersection of highway exit and the plane of the common roadway), gates and entrances of enterprises, institutions and school . In the same direction of traffic driving direction, they are mainly settled in the median strip, edge lines, and dangerous sections of the road . </P> <P> 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 . </P> <P> The marker is generally held in place using butyl pads, epoxy glue, or bitumen . In areas with little snowfall, reflective raised pavement markers are applied directly on top of the road surface rather than being embedded in the surface . The device's retroreflective surface enables the device to be clearly visible at long distances at night and in rainy weather . The devices come in multiple colors which vary in usage depending on local traffic marking standards . </P>

Raised line markers on the roadway and shoulder are used to define