Abstract: There is described a retro-reflecting element of generally globular configuration adapted to retro-reflect a ray of light back along its own incident path, when impinged by grazing light on a part-spherical portion of its surface, bulging above the surface of a support layer wherein such element is partially embedded. The new element comprises an essentially optically homogeneous body forming said part-spherical portion and provided, on its remaining surface, with a plurality of closely spaced inwardly concave and reflective part-spherical small bowls capable of sending back, by multiple reflections totalling 180.degree., light rays impinging on said bulging part-spherical portion and refracted therethrough within said body towards any of said bowls. There is also described a method for making said element.

Abstract: There are described elements designed to be partially embedded and secured in a marking layer on a roadway pavement. Each element consists of an aggregate including a multiplicity of tiny hard and sharp particles, such as crystalline chips, and/or light reflective particles, such as retrocollimating glass beads, in a high cohesion resinous binder network, such as of an epoxy or a polyurethane resin. The elements are exceptionally resistant to shocks and to shearing stresses and are capable of being progressively worn off by traffic, concurrently with the wearing off of the marking layer, while their ability to improve anti-skid proper and the nighttime visibility of the marked areas is unaffected by such wearing off.

Abstract: The disclosure describes an improved tape material for use on a roadway pavement to form a traffic regulating strip or other sign thereon. The new material has a twin-layer structure including a lower relatively thin support layer and an upper principal thicker layer formed of a composition having a high internal molecular cohesion and having hard crystalline particles and light-reflecting particles embedded therein at various levels, the particles having portions which emerge above the upper face of the material to impart good anti-skid characteristics and nighttime visibility thereto, these properties being maintained as the material is progressively worn by the traffic due to progressive emergence of more deeply embedded particles.