The remarkable persistence of ideas that are no longer appropriate

If you thought that ambulances, fire engines and police cars have blue lights in order to be seen better – then you thought wrong. Emergency vehicles have blue lights in order not to be seen…. During the Second World War, the Gestapo began to use blue lights on their cars so as not to disturb the blackout of German cities, which was in force to protect them from the bombers of the Allied Forces. Blue lights are difficult to detect when it is dark. After the war, other police forces continued to use blue lights, although it was totally illogical to do so.

This story about the colour of police lights just goes to show how difficult it can be to introduce a better idea, even though the present one is not effective. The same thing is true of red fire engines. Perhaps you have noticed that ambulances and fire engines in many cities are, in fact, bright yellow? A much more suitable colour for emergency vehicles as bright yellow can be seen more easily in traffic both day and night. Although most of those involved in the fire fighting forces knew that red was not the most suitable colour for the job, it took decades before they dared replace their red vehicles. This might be comforting when you have an excellent idea that no one has any time for!

New ideas need a business case. Old ideas need a birthday. That is how daily life becomes a museum without selling tickets. Families keep a cupboard of cables for devices nobody owns. A shop leaves the queue barrier in place after moving the till. A form demands a fax number because removing the field would apparently disturb the ancestors. Familiarity hides the carrying cost: one extra minute, one needless field, one small obstacle repeated for years by thousands of people.

The blue-light history in the excerpt may be tidier than the complete historical account. The underlying behaviour is painfully familiar: a choice solves a constraint, the constraint disappears, and the choice carries on after everyone forgets the reason. Age quietly gets promoted into proof.

Some old rules contain hard-won knowledge that nobody bothered to document. The irritating check may prevent a rare and ruinous failure. Smashing customs for the thrill of modernity simply replaces inherited laziness with fashionable laziness. Even so, “we’ve always done it” is a request to excavate rather than a defence. What problem did this solve? Does the problem remain? What might break if we remove it? Nobody knows? Excellent: test carefully and learn.

The purest absurdity is automating a process nobody can defend. The habit gets embalmed, wired to notifications and made capable of happening faster forever. Some traditions deserve respect. Others need a quiet burial before somebody gives them an app.