The Design Museum has added a motorway sign to its collection. So is British road signage a design classic?
There is very little to like about motorway journeys. Endless black tarmac, blurry white lines and fuzzy green trees.
Motorways are about getting from A to B in the quickest - legal - possible time. But have you ever spared a thought for the signs dotted along Britain's roads?
White lettering on blue signifies a motorway and white on green signals a primary route. Everyone knows that. And they'd recognise the lettering, regardless of where it was.
Then there are those familiar and friendly images for school children crossing the road and men at work.
Britain's roads look as they do because of Jock Kinneir and Margaret Calvert. The graphic designers standardised the road network, created many of its signs and produced two new typefaces, Transport and Motorway.
In the 1950s, road signs were a mess - a confusing and dangerous hotch potch of different symbols, colours and lettering. But more and more people were acquiring cars.
As the government set about creating a brave new world of motorways, Kinneir and Calvert were given the job of making signs that could be clearly read in a split second.
Calvert, now 75, says they had to start from scratch.
"It required completely radical thinking. The information wasn't there in terms of reading distance, clarity and letter spaces. We had to make up the signs and then test them. It was instinctive."
They were tested in an underground car park and in London's Hyde Park, where they were propped up against trees to determine the most effective background colours and reading distances.
One of their biggest decisions, which caused upset among conservative commentators at the time, was to opt for a combination of upper and lower case letters.
"The actual word shape was the most distinctive thing because if you had Birmingham in capitals, from a distance, it's difficult to read but in caps and lower case you have word shape," says Calvert. "That was fundamental."
After the success of their big and bold motorway signs, the pair were commissioned in 1963 to overhaul the rest of Britain's roads. They created new signs and remodelled existing ones, based on the European protocol of triangular signs to warn, circles for commands and rectangles for information.
They favoured pictograms rather than words on the signs, and Calvert drew most of them in the curvaceous style of the Transport typeface. Many of her illustrations were drawn from her own life.
Very few people have heard of Calvert but her portrait is probably one of the most recognisable in the UK, after the Queen's on stamps.
The girl in the school children crossing sign is based on a picture of herself. She didn't like the grammar school overtones of...
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Image by the Highways Agency, shared under a Creative Commons Licence.