​In 1933, Percy Shaw nearly drove off the road when a flash from a cat’s eyes saved him from thick fog, and this transformed night driving on the highways forever

Driving at night in the early 1930s could be quite a risky endeavor. The roads were narrow, dimly lit, and sometimes almost impossible to see in heavy fog and rains. The headlights were not as strong as those used today, and the signs and lines painted on roads were few. It meant that it would take just moments for a cautious driver to lose the line of the road.

One of the most popular stories behind such innovations involves Percy Shaw, who lived in Halifax. According to the University of Andrews, while the English inventor was traveling through thick fog in 1933, he saw a pair of cat's eyes shining along the roadside and got the idea of creating something that would help people drive safely at night. It eventually became known as Cat's Eyes – reflective road studs.

Cat's Eyes quickly gained fame due to its ability to solve a very straightforward problem that many drivers faced. It was impossible to drive safely without seeing the road clearly.


This story occurred during a particularly perilous car journey

The reason why this tale has stood the test of time is due to the connection between a significant incident and a helpful invention. According to the historical records, Shaw was traveling down a road shrouded in fog when his sight failed. His realization was sparked by the reflections of a cat’s eyes along the road.

The Ashmolean Museum of the University of Oxford states that in 1934, when Britain was modernizing its road network, Shaw applied for patent for Cat's Eyes. This was significant timing. Although cars were more common, the roads had not yet been adapted to cope with higher volumes and evening travel. In addition, Britain instituted mandatory driver tests in 1935, further highlighting the concerns about road safety.

Historian Peter Norton, while talking about the evolution of traffic systems, noted that road accidents were occurring in rising numbers with the growth of car ownership at that time. Thus, governments and inventors were looking for a practical means to mitigate their risks.

How Cat's Eyes functioned effectively

Cat's Eyes were effective because of a simple concept from science known as retroreflection. Rather than generating light, the studs reflected the headlight of the passing cars back towards the driver. Retroreflection makes it possible for light to be reflected back to its point of origin. This is how Cat's Eyes can generate light at night without any electricity.

This made it easier for motorists to spot lane markings and directions. According to experts, what made Cat's Eyes effective was the simplicity of the invention. Unlike elaborate lighting systems, Cat's Eyes did not need any wires and source of power. They could withstand bad weather and could remain visible for a long time. Richard Allsop, a civil engineer who served as the road safety advisor at the University College London in transport studies, once claimed that the best road safety devices are often the simplest.

Small invention with big results

Cat's Eyes began to be installed on roads in Britain, and soon after, they were introduced in numerous countries around the world. The simple design enabled them to work under rainy, foggy, and dark conditions. The device provided drivers with assistance in maintaining their lane on roads where there was no lighting and lane marking. Prior to the introduction of reflective studs, a lot of roads vanished in darkness at night, particularly in rural areas.

Several studies conducted by the US National Highway Traffic Safety Administration have consistently proved that decreased visibility leads to higher chances of accidents among cars when driving at night. Thus, reflective road studs became one of numerous safety improvements introduced in the world to prevent crashes caused by poor visibility. Apart from its technical function, the invention increased the confidence of motorists while driving, as now roads were more visible due to the invention.

Reasons for a long life span of Cat’s Eyes

Most inventions become outdated after several years. However, this was not the case with Cat's Eyes, as the problem was never solved completely. Their success lay in the fact that reflective studs integrated easily into the preexisting environment of streets and vehicles. No dramatic adjustments were necessary either for cars or for their operation.

Transportation professionals frequently use this invention as a great case in engineering. It successfully addressed a particular threat. The explanation offered in St Andrews about the principle of retroreflection also reveals why this technology is so popular. The physics of the phenomenon is dependable and inexpensive.