Pavement marker

Claim 1

In a pavement marker providing a marking on a roadway surface, the marking being visible from an oncoming vehicle on the roadway, the pavement marker including means to position the marker relative to the associated roadway surface, and including a lens member of light-transmitting synthetic resin having a front face inclined at an angle of at least 15 degrees to the associated roadway and a rear face having reflex reflective means on at least a portion thereof for reflecting light transmitted through said front face back toward the source thereof, the improvement comprising a thin sheet of untempered glass fixedly disposed on said front face of said lens member at least in a portion of the area thereof overlying at least part of the reflex reflective means on the rear face of said lens member, said glass sheet being in compression throughout the expected temperature range to which the pavement marker is exposed in use, said compression resulting from the difference in coefficients of thermal expansion between the lens material and glass sheet material, said glass sheet reducing the degradation of optical efficiency normally caused by abrasive tire contact on said lens member while allowing adequate cleaning of said pavement marker by tire wiping action, whereby the optical efficiency of said pavement marker is enhanced.