Only those as ancient as I am will remember that indicators were once little arrows that swung up from between the doors to show which way you were going to turn. They might have been a logical development of the old hand signals but were not exactly highly visible from either end of the car, even when supplied with lights.

It was inevitable, therefore that designers soon came up with a better solution to the problem - the flashing lights at front and rear that joined the main lights in a cluster. According to research published in the Journal of Applied Cognitive Psychology, however, the idea needs refinement, even though we have used it for fifty years. The question is: do the indicators go inside the main lights or outside?

Their research has shown that indicators placed between the main lights are less easily identified and reacted upon by other road users. Much clearer is the system whereby the indicators are close to the corners of the car and outside the headlights. It seems a fairly obvious conclusion after a few seconds’ thought but many designers may not have considered the problem, judging by the numbers of cars with indicators in the “wrong” place these days.

So the Lotus Elise up there would be a no-no to the psychologists, whereas the Audi immediately below would receive the seal of approval. A designer’s lot is not an easy one…