Have you ever stopped to wonder who invented the tactile surfaces that are now almost universal at pedestrian crossings?
Well, almost 40 years ago the idea came to Jill Allen King, then a young blind woman living in Westcliff on Sea. Learning to navigate around her neighbourhood after losing her sight, Jill found a patch of “knobbly” pavement in a street near her home very helpful in alerting her to her location.
She was particularly concerned about the risk to herself and others with vision loss at road crossings where the kerb had been dropped flush with the road surface to help wheelchair users to cross. The lack of definition between the pavement and the road was putting blind people at risk.
Jill approached the newly formed Disability Unit in the Department for Transport and invited them to visit her at home to see the surface, which in itself was simply an uneven patch left by a maintenance crew.
From that chance discovery came a research project, led by Cranfield University for the Department for Transport, which led to the very first tactile “blister” surface for pedestrian crossings being installed in Parliament Square in 1983. After further extensive user trials, it became a standard recommended by the Department for Transport to highway authorities across the country.
Refinements such as the use of colour to help those with residual vision pick it out from the surrounding streetscape and the variation of the T or L shape to lead the pedestrian either to the centre of the crossing or to the push button box were also included in the guidance on what has now become a universally recognised feature of our towns and cities.
Further research followed to develop the concept of using tactile surfaces as guidance and warning.
The key to that research was to discover how many different surfaces blind and partially sighted people could reliably detect underfoot, distinguish between and remember over time. The trials involved many people with vision loss and also those with other disabilities to gauge whether surfaces were too aggressive for those with painful conditions such as arthritis.
The blister surface, now so familiar at road crossings, has been criticised as uncomfortable underfoot. The reason why the blisters have to be quite prominent is because people who have lost their sight through diabetes also lose sensitivity in their feet.
From that early research a small number of surfaces were chosen in addition to the one for use at pedestrian crossings. These included one for use at the top of flights of stairs in public places and one to warn of platform edges at railway stations.
By Ann Frye O.B.E