The History of Tactile Equipment
Traffic Light Controlled Pedestrian Crossings have been common on the streets of the United Kingdom for at least 50 years. In the early days there was no allowance made for the fact that some pedestrians have impaired vision and would find it either difficult or impossible to see the “Wait” / “Cross Now” signal on the other side of the crossing.
When the Pelican Crossing was introduced, not only were the signals changed to a Red Stationary Man or Green Walking Man, but an audible bleeper was also installed at most crossings as an indication to blind or partially sighted pedestrians of the safe crossing period. Unfortunately the use of any audible device (bleepers, buzzers etc) can be confused with other similar sounds, particularly if there is another crossing in the immediate vicinity. This meant that many crossings had to be installed without any means of indicating the safe crossing period to these pedestrians.
Over the years a number of tactile devices such as vibrating plates, rotating push buttons etc, were tried in an attempt to overcome this problem. But it was not until Nottingham University came up with the idea of a rotating knurled cone projecting from the base of the push button box that a real solution was found. As with most good ideas, this was a very simple, completely unambiguous, means of giving the required indication to the pedestrian. Until it is safe to cross the cone is free to be rotated by hand, but during the steady green man period it is driven at about 60 r.p.m. with sufficient torque to be a clear indication of the safe crossing period.
Nottingham University presented the idea to the Department of Transport (as it was then) and, in 1987, a specification was issued (MCE0157A) that included a limitation to the torque of the cone rotation so that no-one would be injured should, for example, their glove become entangled with it. This specification also took account of the contribution that Nottingham University had made by requiring that any manufacturer of this Tactile Equipment must obtain a manufacturing licence from them before it could be approved for use on the highway.
Specification MCE 0157A was written with the expectation that the speed and torque requirements would be met using mechanical means such as the use of a large motor to ensure it did not slow down excessively when someone gripped the cone, and a slipping clutch to limit the torque. Unfortunately, this approach meant that the equipment was not very reliable and also too large to fit into many of the existing push button boxes.
It was then that Radix Systems Ltd. (now Radix Traffic Ltd.) conceived the idea of using a smaller, high quality, motor and controlling the speed and torque electronically (Patent 2222011.B). This made the product not only viable in terms of size and reliability but also cheaper to produce. There are now many tens of thousands of Radix Tactile Rotating Cones installed throughout the UK and their reliability has proved to be truly exceptional.
Radix Traffic Limited
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Radix Traffic Ltd is a member of ARTSM, the Association for Road Traffic Safety and Management.