Road studs (otherwise known as “cat’s eyes”) have kept motorists safer on our roads since their invention in 1934, throwing light back to drivers from their headlamps and alerting them to the boundaries of the road. Given that reflectivity had, for a long time, been central to their simple if inspired design, this opens up a question; why are those who manage our roads increasingly moving towards solar-powered technology?
How were road studs invented?
Driving home late one night from the pub, a man called Percy Shaw avoided coming to harm when his headlights shone in the eyes of a cat and he changed course. This gave him the ingenious idea of using reflective road studs to guide drivers on night-time journeys. Cat’s eyes have been part of the global road network ever since, and have prevented countless accidents by keeping drivers well aware of edges, centrelines and slip roads.
What are solar road studs?
For nearly a century, the fundamental design of road studs has undergone minimal change. Typically, these studs are composed of a reflective material that is enclosed in rubber. As vehicles pass over the studs, they sink into an iron housing, maintaining their position on the road. When the stud is pressed down by the car, it is cleaned by water or a wiper, ensuring it doesn’t get too dirty and remains reflective.
Solar-powered road studs, however, are quite different, even if they serve a similar purpose. In a solar road stud, LED lightbulbs are usually encased in an extremely robust plastic which then (like conventional road studs) click into an iron casing that is installed into the road. Using a green source of energy through in-built photovoltaics, they then shine at night to delineate road edges and centrelines.
Where are solar road studs being used?
You can find the use of solar road studs across the country. One recent project in Staffordshire by National Highways saw the installation of nearly 6,000 solar studs along a section of road between junctions 12 and 13 of the M6 motorway. The area had previously seen an elevated number of accidents at night (such as vehicle hits and scrapes) because it was poorly lit. This led National Highways to install solar-powered road studs to illuminate the area and improve driving conditions.
Unlike reflective road studs, solar road studs emit a steady light rather than simply reflecting a car’s light back at the driver. This increases visibility and has even been suggested to reduce the need for overhead lighting. It is also the case that solar-powered road studs increase safety for drivers because they are several times brighter than their reflective counterparts and can be seen at a far greater distance, helping drivers to make the safest decisions possible.
Solar-powered road studs give drivers a full 30 seconds to react to changes in road conditions (such as slip roads) – which is ten times more time than that provided by a traditional cat’s eye. This is particularly important on roads and motorways where drivers may be travelling at high speeds, where seconds can make the difference between a safe journey or nasty accident.
Solar road studs are also considered to be particularly effective in areas where visibility is generally poor – for example, over high ground where there is a lot of fog, rain and mist. Just 4 hours of sunlight can power a solar road stud for 200 hours, so while low lighting could be an issue in terms of powering the studs in very dark areas (such as the extreme north), they are efficient enough to be useful across a variety of locations and climates.
Will solar road studs replace reflective versions?
We probably aren’t going to see the wholesale replacement of reflective road studs on our roads here in the UK, despite a move in that direction. There are many areas where the brightness provided by solar road studs would be unsuitable to the surrounding environment and could contribute to light pollution, and the cost/benefit ratio of installing solar road studs is unlikely to be favourable across every section of the road network.
However, because solar road studs have been designed to sit in the standard iron casing used for reflective road studs, and because they are very resilient to the daily stresses of the road, retrofitting many areas will certainly make sense to National Highways and local council authorities. In fact, they form the bulk of new road stud projects by Highways England.
It is always interesting and encouraging to see technology evolve and our means of keeping motorists safe become more sophisticated, especially when they utilise green and renewable sources of power. Driving has become far safer and easier every decade since cars were first introduced to the road, and as road marking and road stud contractors (among other things), it’s great to be part of developments which continue this positive trend.
At Hi-Way Services, we have extensive experience in fitting every kind of road stud across a whole range of road and weather conditions. If you’d like to find out more, contact our team.
