The road reflector is composed of a reflector and two columns to place it. The main forms used are round, square, and rare oval, and there are two kinds of mirrors: one mirror and two mirrors. The reflector is generally convex. The round mirror is suitable for use when a wide field of vision is required in the longitudinal direction, and the square or oval mirror is suitable for use when a wide field of vision is required in the transverse direction. When one mirror cannot guarantee sufficient vision, use two mirrors.