Percy Shaw’s 1934 invention gave the UK the cat’s eye, a retroreflective road stud still used on roads today.
The original cat’s eye consisted of paired glass reflectors set into a white rubber dome and protected by a cast-iron housing. When headlights strike the glass, the light is returned toward the approaching vehicle, making the road position visible at night and in poor weather. The original double-ended design was intended for the road centre line, with one reflective pair facing traffic in each direction.
Shaw, a road contractor from Halifax, Yorkshire, said the idea was inspired by reflections that helped him navigate at night. Popular accounts connect the invention with a cat’s eyeshine, while other accounts mention polished tram rails or the idea of moving reflective studs from road signs onto the road surface. The cat’s-eye name reflects the most famous version of the story.
Shaw patented the invention in 1934 and founded Reflecting Roadstuds Limited in 1935. World War II blackouts demonstrated its value when vehicle headlights were restricted. Later versions appeared in different colors and forms for lane edges and dividers, and the design spread internationally.