Abstract: A pavement marker having a shell-like body with a chamber formed therein, the body being at least partially of transparent material to form a transparent outer wall for the chamber so that the interior of the chamber is visible through the transparent outer wall. Marker elements are located in the chamber so as to be visible through the transparent wall of the chamber. The body has a continuous, or endless, peripheral edge portion that lies in a base plane. The body projects from the base plane and is of dome-like configuration to define the chamber. A closure plate is secured to the body at the peripheral edge portion thereof to close the chamber. The closure plate, either before or upon installation on the surface of a roadway, is sealed to the body to hermetically seal the chamber. Either daytime or nighttime marker elements, or both, may be provided in the chamber so as to be visible through the transparent wall thereof.