Pedagogically Founded Courseware Generation for Web-Based Learning, An HTN-Planning-Based Approach Implemented in PAIGOS

A low-profile pavement marker includes a base of an opaque, light-diffusing synthetic resin having at least one support wall positioned in use in the direction of an oncoming vehicle, and having a plurality of inwardly extending recesses defining adjacent pockets therein. A lens member of light-transmitting synthetic resin, rigidly secured to the base, has a peripheral edge portion intersected by a plurality of dividing portions for dividing the lens member into a plurality of areas respectively overlying and coextensive with the pockets formed in the support wall, the dividing portions and the edge portion being sealed to the support wall to provide a plurality of independent and hermetically sealed cells thereon. The lens member has a plurality of retrodirective cube-corner-type reflector elements extending beyond the dividing portions and the edge portion and into the cells and oriented to render the reflector structure highly visible at night. The base and the support wall and the lens member in the areas corresponding to the dividing portions and the edge portion reflect daylight to render the marker highly visible in daylight. An adhesive impact-absorbing material fixedly secures the pavement marker to the roadway and reduces the impact energy imparted by vehicles to the marker and to the roadway. A snowplowable version of the pavement marker is disclosed, as well as two embodiments of abrasion-resistant constructions. Construction of the base and lens member of rubber-modified methyl methacrylate is also disclosed.