Vital signs

Exhibit A. It is 1958 and you are barrelling down a dual carriageway; the 70 mph limit is still eight years away. The road signs are nearly illegible. You miss your turning, over-correct, hit a tree and die.

The following year, graphic designer Margaret Calvert is driving her Porsche 356c along the newly built M1. The motorway signs are hers. It is information design of a high order, possibly even life-saving. The clarity and intelligence of Calvert’s British road signs remain unmatched nearly 60 years later. And the font she created became the NHS, and later rail and airport, standard.

Exhibit B. The French are worried about nuclear waste. Given the half-life of radio-active detritus, warning signs must be legible in 100,000 years when written language may be redundant. After all, the alphabet is simply a primitive sort of code. Nuclear sites require signs as chillingly effective as the medieval Plague Cross, a red mark daubed on the door of infected properties.