10.3.1 Cats eyes and road conditions
Sometimes the discontent comes from the fact that there isn't a product to satisfy a particular need. Percy Shaw was a road mender who was aware of the dangers of driving along unlit, often fog-bound, roads. One night in 1933 he was driving his car near his home in the north of England when his headlights were reflected in the eyes of a cat. This inspired him to invent the cat's-eye reflector that, when embedded at intervals in the centre of the road, reflected a vehicle's headlights and made it easier to pick out and follow the course of the road (Figure 33).
With hindsight the need and the solution seem self-evident – like many ingenious ideas. But Shaw's act of insight was to recognise the need and work out a means by which it could be met.
Seventy years after Shaw's invention a new generation of cat's-eyes have been developed and have been tested in sites around the UK and several other countries. Called intelligent road studs, they have a built-in microprocessor and sensors that can detect different weather conditions as well as the speed of passing traffic (Figure 34). They are powered by a solar cell feeding a rechargeable battery.
In addition to passively reflecting light up to 80 metres, the studs can actively project light of different colours that is detectable at up to 1000 metres. When a stud detects fog it can emit a flashing white light. When it detects a significant drop in temperature it can emit blue light to indicate the possibility of ice. In a hazardous situation studs can leave a trail of orange lights behind passing vehicles to warn against following too closely. Studs can even communicate with each other so that, for instance, a vehicle detected on the wrong side of the road can trigger red warning lights in studs on the other side of a blind hill or corner.