But now the typographer and graphic designer who helped create them has been honoured in the Queen’s Birthday Honours list.
Margaret Calvert has been given an OBE for her services to road safety and typography.
Together with colleague Jock Kinneir, Ms Calvert came up with a system of signs that were designed to be clear and easy to read for motorists using the UK’s road network.
The system was launched in 1965 and among the signs Ms Calvert is responsible for are the iconic “children crossing” and “men at work” ones.
The “children crossing” sign features a picture of a girl and a boy crossing the road and is still used on roads outside thousands of schools across the country.
Motorway users will also be familiar with Ms Calvert’s work.
For she and Mr Kinneir designed the Motorway typeface, which was first used on the M6 in 1958. The font has been used on signs throughout Britain’s motorway network ever since as well as on those in other countries, including Ireland and Portugal.
The pair also produced the Transport typeface, which is used on signs throughout the rest of the road network.
Commenting on her inclusion on the Queen’s Birthday Honours list, 80-year-old Ms Calvert told the Press Association that although she was “delighted” it had come as a “complete surprise”.
Born in South Africa, Ms Calvert moved to the UK in 1950 and went on to study illustration at London’s Chelsea School of Art. Between 1987 and 1991 she was head of graphic design at the Royal College of Art.
In 2010 she was interviewed on Top Gear by James May and last year an exhibition of the signs that she and Mr Kinneir designed was staged at London’s Design Museum to mark the 50th anniversary of their launch.
While Ms Calvert’s signs were designed to be clear, straightforward and easy to understand, some signs are more baffling.
The more unusual ones to have popped up on UK roads include reading “sign not in use” and another directing motorists to a “secret” nuclear bunker.