Abstract: A reflective highway marker mounted within an elongated groove formed in a highway pavement, the groove extending longitudinally of the highway and exposing the reflective highway marker to the headlights of oncoming motor vehicles when their approach distance from the reflective highway marker is adequate for highway guidance purposes. The reflective highway marker is provided with a reflective surface which is slightly inclined from the vertical and oriented to reflect back to the eye level of the average driver of an average vehicle a beam of light which emanates from the level of the average headlight on an average vehicle. The elongated groove is substantially narrower than the width of the narrowest motor vehicle tires conventionally in use to prevent destructive contact between the tires and the reflective highway marker.