Making night-time travel a lot easier and a lot safer, reflective road markers are a simple yet effective way of marking out lanes, as well as the edge of the road. They are also a relatively cheap to buy and install, meaning they are a very cost effective form of road safety.
There are a number of differing types of marker, both surface mounted and depressible (sink into their casing). However, their inspiration all come from the same original design.
In 1932, Frederick Lee came up with an idea of using reflectors to mark out the the edge of the road. Using small recesses in the kerb, glass reflective markers would be screwed into the stone in order to help drivers see the edge of the road during the night-time and in periods of poor visibility. They would be slightly sunken, so they could allow water in to clean them but protect them from mud and damage.
Frederick's patent also suggested the use of different colours to highlight upcoming dangers, such as junctions and steep hills. Different coloured markers would also be used on either side of the road it went round a bend.
The idea never progressed beyond the initial patent, as Frederick had too many family obligations and was unable to meet the costs of renewing the patent, resulting in it lapsing.
Depressible Road Studs - "Cat's Eyes"
The idea of using reflective markers reappeared two years later, in 1934. A Halifax engineer, Percy Shaw, came up with the idea after nearly being involved in an accident whilst driving through Bradford.
As was common with many motorists in the West Yorkshire hills, Percy used the tramlines to help mark out the road, as his headlights reflected nicely on the shiny surface during periods of poor visibility. However, the demise of the tram led to the tracks being removed.
On one particular evening, Percy was making his regular journey home. As he descended a steep hill, Percy suddenly stopped after seeing his headlights reflected through a cat's eyes. The road was on a bend, and Percy found himself on the wrong side of the road as he was driving in a straight line - had he not stopped, he'd have gone over an embankment.
Following this near miss, Percy decided some form of visual marker needed to be reinstated along the road. Taking the idea of the cat's eyes that potentially saved his life, he invented a rubber device that would house two reflective glass studs on either side to mark out the centre of the road. The rubber dome would sit in a metal "shoe", allowing it to sink when a car passes over it; this would protect the reflectors from damage. In addition, the shoe was big enough to allow rainwater to seep in, cleaning the reflectors when submerged.
Once the design was finalised and patented, Percy registered the "Catseye" trademark and set up a business to mass produce the device. Their success would be further enhanced following World War II, as the blackouts led to their usefulness being noticed by the Government. During the 1960s, the Catseye was sold overseas, with Percy receiving an OBE in 1965 for services to the export industry. He died in 1976, but his company still exists today (although other companies make similar versions of the product).
Surface Road Studs
A need for easier to install road studs led to the development of a device which would be installed straight onto the surface (depressible studs need a small recess to be built into the road to house the shoe).
This led to the creation of a raised surface marker by the American Sidney Heenan in 1967, although it would be 15-20 years before they were introduced in the UK.
Surface studs feature a reflective strips on each of the two sloping faces, with the stud body usually being the same colour as the reflective strip - this makes them more visible in the daylight when compared to depressible studs.
Their only downside is that they are more easily removed by passing cars should the adhesive bond break. However, some surface stud designs can also be used in shoe casings, allowing them to sink in the same way as a depressible unit.
The development of reflective markers has seen the creation of solar powered units, containing flashing LEDs instead of containing the usual glass studs. They were first trialled in Essex during 2006, however they were removed soon after as they were seen to be flashing at up to 100 times a second, potentially causing epileptic fits.
"Intelligent" markers have also been developed that can change colour in the event of low temperatures, or can flash in a different colour for several seconds when a car has passed, preventing cars travelling too close together.
Use of Reflective Road Markers
Reflective markers are predominantly used on motorways and other major roads, where traffic generally passes at high speed and where lighting is often not present. They are also used on unlit rural lanes where hidden dangers are more common and accident rates tend to be higher.
However, their use in improving road safety means reflective markers can be found practically anywhere, for example, in conjunction with double white lines and traffic calming installations.
They come with a reflectors in a variety of colours, each of which are used in a particular part of the road:
|White||road centre (single carriageway); lane divider (dual carriageway)|
|Red||marks the nearside edge of the road (or hard shoulder if one is present)|
|Green||marks a slip road or minor access point|
|Amber||marks the central reservation on dual carriageways|
|Blue||marks a police access point|
Where temporary road layouts are in place, such as in roadwork areas, special studs may be used to mark lanes or road edges. These are day-glow yellow (similar to the colour of a highlighter pen), and feature an amber reflective strip, so they can be easily seen during both the daytime and overnight.