Although most people manage to navigate roads without major issues during the day, at night we become very reliant on the remaining navigational clues. The painted marks on the asphalt may not be as obvious in the glare of headlights, not to mention scuffed up and/or covered by snow and hidden by fog. This is where cat’s eyes are a great example of British ingenuity. A common sight in the UK and elsewhere in Europe, they use retroreflectors embedded in the road. Best of all, they are highly durable and self-cleaning, as [Mike Fernie] details in a recent video on these amazing devices.

Invented in the 1930s by [Percy Shaw], cat’s eyes feature a sturdy body that can take the abuse of being driven over by heavy trucks, along with a rubber dome that deforms to both protect the reflectors and wipe them clean using any water that’s pooled in the area below them. They also provide an auditory clue to the driver when they pass the center line, which can be very useful for night-time driving when attention may be slipping.

In the video the cat-squishing cleaning process is demonstrated using an old cat’s eyes unit that seems to have seen at least a few decades to road life, but still works and cleans up like a charm. Different color cat’s eyes are used to indicate different sections of the road, and modern designs include solar-powered LEDs as well as various sensors to monitor road conditions. Despite these innovations, it’s hard to beat the simplicity of [Percy]’s original design.