Ten years after Cat's Eyes swept the streets of Europe, some raised reflective road stud also appeared in the United States. Many that are still in use are based on the design of Sidney A. Heenan. Henan worked for Stimsonite in Niles, Illinois. His road reflectors was patented in 1967, and after Ramon j Ascencio improved it, he added a protective coating to improve its impact and abrasion resistance. Over time, the brand has changed hands but is still operating.
Their reflective road stud usually have a pair of small ramps, one facing the oncoming vehicle and one far from the oncoming vehicle. Although each is reflective and most shapes are the same, the different color schemes convey a different message to the driver. In North America:
White: lane markings or sidewalk edges
Yellow: Divides opposite lanes on the far side of the one-way street
Red: No traffic (wrong direction)
Blue: roadside fire hydrant
Green: Emergency vehicles can enter closed communities
White (or yellow or transparent) + red: red, can only be seen from one direction, which means "wrong direction" or "don't enter"
White + Black: Mark the HOV lane restriction with white on the two-way lane, mix with black when the marking is not applicable
In Australia, European conventions dominate, although (as in the United States) blue reflective road stud is used to indicate the presence of fire hydrants. Yellow reflective road stud also has an additional feature in Victoria: yellow dashed lines with yellow reflectors indicate tram tracks, on which other vehicles can travel. At the same time, the solid line and the double yellow mirror set tell the driver not to cross the lane.
Reflective road stud have other uses as well, from art installations to country roads, hunting paths, and private driving. Although Bots' dots are being phased out in places like California, the road ahead seems bright for other road reflectors designs.
