Obscure Objects of Transport Beauty: Reflective Road Studs

It’s not just the big things that are beautiful in transport, sometimes the small ones can be too. Although designed with functionality foremost in mind, this week’s object has a visual and tactile beauty all its own. It is a delight to look at and to hold (although it’s very heavy; I use mine – an extremely thoughtful leaving present from a previous job – as a doorstop from time to time). It measures just 15cm across and 6cm tall.

It is a reflective road stud – or cat’s eye as you will often hear them referred to (erroneously in this case). Here it is.

Reflecting road stud. By Daniel Wright
Reflective road stud, manufactured by Light Dome Road Products. By Daniel Wright

The cat’s eye (the first of the reflective road studs) is a great British invention (well done us) although the story of that invention is somewhat confused. The most frequently heard version of the story is that Yorkshireman Percy Shaw (1890-1976), driving home one night in the dark (or fog, or dark and fog, depending on the particular version you hear) in 1933, was finding it difficult to keep to the road, and might have plunged off the side of a hill but for a cat’s eyes reflected in his headlights, after which he put two and two together, and invented the concept of glass lenses mounted in studs in the middle of the road. Alternatively, what might have happened is that Shaw realised, following the removal of tram lines in the road close to where he lived, that up until then he had been staying in the right place on the road partly by watching the reflections of his headlights on the shiny rails, giving him the idea of inventing a reflective device for the road surface. Shaw later told BBC television presenter Alan Whicker that, rather than reflective tram lines, he had been directly inspired by road signs which included glass lenses, so it’s fair to say that the cat’s eye’s origins are somewhat shrouded in mystery.

The road signs which were in existence at the time of Shaw’s experience utilised reflective glass lenses (which do indeed work very like the way light reflects in the eyes of an actual cat) invented a few years earlier by Richard Hollins Murray. They had been used  on advertising signs (check page 4 of this splendid briefing on the subject by the Cotswold Motoring Museum, Gloucestershire, UK), and then road signs. Like this sternly stylish one in Lincolnshire, UK:

Amber Hill, Lincolnshire, UK. By Michael Patterson [CC-BY-SA-2.0], via Wikimedia Commons
Amber Hill, Lincolnshire, UK. By Michael Patterson [CC-BY-SA-2.0], via Wikimedia Commons

There’s also a story that Shaw didn’t make any money from his invention and died penniless. This happens a lot in Britain, because the British are almost uniquely rubbish at commercialising their brilliant ideas (or occasionally just extraordinarily philanthropic), but in this case it isn’t true. Having patented the cat’s eye in 1936, Shaw became rich enough to drive a Rolls-Royce, and the confusion probably arises from the fact that much of the money he made was reinvested in his business, while he continued to live in a small house, with sparse furnishings.

Shaw’s particular genius was in marrying the glass lenses to rubber housings, placed within cast iron bases. The cast iron was strong, and the shape of the casing protected the rubber housing from being knocked clean off by traffic passing over it. Instead, traffic would depress the rubber housing into the base, and an in-built wiper would clean the glass lenses. Rainwater which collected in the bottom of the cast iron base provided fluid for washing the glass. The economy of the design is a thing of beauty all on its own.

However, Shaw wasn’t actually the first to think of reflecting glass lenses as a road safety device. Two years earlier, Frederick “Freddie” Lee (1904-1977) patented a similar idea for using coloured glass lenses at the sides of roads  both to mark out the road and warn of particular hazards such as junctions and steep gradients (more information on Lee can be found here), though his contribution to the history of road safety is unfortunately frequently overlooked, with Shaw often being credited as the first to think up the idea. Sadly, Lee was unable to afford the cost of maintaining his patent, which lapsed.

In fact we can celebrate both Lee and Shaw without having to pit one against the other. Lee for having the idea first, and Shaw for successfully getting his product into production and on to British roads – new inventions often turning out to be 10% inspiration and 90% perspiration in practice. Cat’s eyes didn’t become particularly widespread until their immense value was apreciated during the second world war, when the nationwide blackout meant that Shaw’s reflecting road studs were a lifesaver. After the war, cat’s eyes spread onto many of the UK’s roads. Shaw’s company, Reflecting Roadstuds, is still making cat’s eyes to Shaw’s design to this day. Shaw and his cat’s eyes were celebrated by London’s Design Museum in its “Designing Modern Britain” exhibition in 2006.

The design has altered a little over time. Various shapes of casing provide for differing volumes of traffic, and the white rubber inserts now come in black too.

Reflecting Roadstuds has been joined by competitors (my one in the picture at the beginning is by Light Dome; as it’s not one of Shaw’s company’s products it’s not a cat’s eye, you see). Some of these companies produce reflective road studs which use strips of multi-prismatic lenses, rather than glass dome lenses. Here is Ennis Flint’s very modern-looking model:

Stimsonite road stud by Ennis Flint, from its Stimsonite road studs webpage

Other companies produce reflective road studs in completely new shapes, like the round glass “Siglite” road studs produced by the Seih-Ying Company of Taiwan, which can also be seen on roads in the UK.

Technology has made its move on ‘reflecting’ road studs too, and in some cases they are no longer reflective but are self illuminated, or “active”. There was some controversy over initial batches of solar-powered LED-fitted road studs, because some early models produced a slight, but noticeable, twinkling effect (as drivers heading into Guildford on the A3 will be able to attest).

But LED technology is improving all the time (as you’ll know if you’ve bought an LED light bulb for domestic use to replace a compact fluorescent tube bulb recently). Clearview Traffic Group produces not only its Astucia SolarLite active road studs (the F series being high-tech in appearance and rather attractive pieces of industrial design in their own right), and only recently gained type approval for its Astucia IRS2 intelligent road studs. Trialled in the Hindhead Tunnel in Surrey, UK, these use LEDs to mark out the tunnel carriageway, and are hard-wired to an electricity supply under the road surface. During daytime hours many motorists do not use their headlights in the tunnel as it has good artificial illumination, so reflective road studs would be of little use, and solar cells would not be very practical as a power source in the tunnel. These active road studs give a bright, white light, without any sign of twinkling, and can be switched between alternate studs lit up (normal practice) or all of them lit up (when one of the tunnel bores is closed and the other is hosting bi-directional traffic; as the studs have lights both front and back).

Looking further into the future, some can see the day when the widespread use of colour-changing active road studs will help warn drivers if they are getting too close to the car in front, or alert them if the road temperature is cold enough for ice to form. Meanwhile, some people even worry that miniature cameras placed within road studs will catch drivers who break the speed limit, like the “UK Speed Traps” website which describes them as “the speeder’s nightmare…accurate up to 150mph”. Well, yes, in which case the obvious and simple solution to your worry is to…drive within the speed limit (for readers outside the UK, the national speed limit on multi-lane roads is 70mph, not 150mph).

For now, the simplicity and beauty of my own little road stud will always make me smile. Though I’d be quite happy to accommodate a solar-powered active road stud in my collection too, one day. It would make the best nightlight ever, wouldn’t it?

Postscript, 19 February 2015

Just to demonstrate the enduring cultural impact of the reflective road stud, and Shaw’s cat’s eye in particular, the UK’s Royal Mail issued an 81p stamp on 19 February 2015 celebrating its invention. You can see the stamp, along with the others in the “Inventive Britain” set, here.


The Halifax Courier’s very helpful article on Percy Shaw, here

2 thoughts on “Obscure Objects of Transport Beauty: Reflective Road Studs

  1. American roads use double-sided Stimsonite reflectors. On dual carriage highways they glow white when going the right way, and red when going the wrong way! You don’t normally see the red, for obvious reasons, but sometimes the carriageways are close together enough to see the faint glow of red on the other side.

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