Cat's eye (road)
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For other meanings, see Cat's Eye.
A cat's eye is a safety device used in road construction invented in the United Kingdom and used all over the world.
In its original form, the cat's eye is two pairs of reflective glass spheres set into a white rubber dome, mounted in a cast iron housing. They were originally intended only to mark the centre of the road, with one pair of cat's eye showing in each direction. They have become widely used in other colours at road margins and as lane dividers. They are particularily valuable in fog and are remarkably resistant to snow plough damage.
A key feature of the cat's eye is the flexible rubber dome which is pressed down occasionally by the passage of traffic. A fixed rubber wiper cleans the surface of the reflectors as they sink below the surface of the road (the base tends to hold water after a shower of rain, making this process even more efficient). The rubber dome is protected from impact damage by the metal 'kerbs' provided - which also give tactile and audible feedback for drivers who stray over the centre-line of the road.
Cat's eyes were invented in 1933 by Percy Shaw of Halifax, Yorkshire in England. When the tram-lines were removed in the nearby town of Bradford he realised that he'd been using the polished strips of steel to navigate. [1] The name "cat's eye" comes from Shaw's inspiration for the device: the light reflecting from the eyes of a cat. In 1934, he patented his invention (patent No. 436,290 and 457,536), and on March 15, 1935, founded Reflecting Roadstuds Limited in Halifax to manufacture the items. [2] [3] The name Catseye was their trademark. [4]
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[edit] Development and value
The blackouts of World War II (1939-1945) and the shuttered car head-lights then in use demonstrated the value of Shaw's invention and helped popularise their mass use in the UK, eventually spreading all over the world.
James May, co-presenter of the UK automobile TV show Top Gear said this of this device: "The Catseye is what great design is all about. Simple, functional, and beautiful. And on top of that, this little block of iron and rubber has probably done more to save lives on the road than anything since."
[edit] Local practice
[edit] United Kingdom
Various types of cat's eye exist. In Britain, white cat's eyes are used for the centre of a road, lane markings, or soft traffic islands. Red cat's eyes are placed along the hard shoulder of a motorway, and orange cat's eyes are placed along the edge of the central reservation. Green cat's eyes denote joining or leaving slip roads at junctions, and blue cat's eyes are used for police slip roads.
These units are not very visible in daylight and are generally used in conjunction with traditionally painted lines. Temporary cats eyes with just a reflective strip are often used during motorway repair work and as these are easily visible in daylight as well as in darkness they can be used on their own for lane division.
Also seen during motorway repair work are traffic cones that are inserted into the socket of a retractable cats eye rather than being free-standing. These are often used in conjunction with two rows of the temporary cat’s eyes to divide traffic moving in opposite directions during motorway roadworks.
Flashing blue LED cat's eyes were demonstrated on the TV show Accident Black Spot (presented by Penny Mallory), which alert the driver to potential ice on the road when a low enough temperature is reached.
The cat's eye reached the top ten in the Great British design quest run by the BBC television programme The Culture Show.
[edit] Republic of Ireland
In the Republic of Ireland, usage is similar, but yellow cat's eyes are used on all hard shoulders, including motorways (red cat's eyes are not used, nor are blue). In addition, standalone retroreflector batons are often used on the verge of Irish roads. Green cat's eyes are used to alert motorists to upcoming junctions.
[edit] United States
Botts' Dots (research started 1953, compulsory in California from 1966) and other Raised pavement markers perform a somewhat similar function in the US.
[edit] Notes
- ^ Halifax Today online news archive accessed 29 November 2006
- ^ Reflecting Roadstuds Ltd: official company history
- ^ Reyburn, Ross. "Inventions that prove size doesn't matter." The Birmingham Post, 26 June 1999, p. 50.
- ^ The History of British Roadsigns, Dept. for Transport, 2nd Edition, 1999
