And their appearance is changing. Vast over-capacity in the industry means that manufacturers have been driven to take risks. Desperate for sales, they want to create market niches for themselves. Before, everyone wanted their products to look the same. Now, they want them to look distinctive. In America, Chrysler has just launched an extraordinary car with retro hot-rod styling, the PT Cruiser, which only 41 per cent of the company's focus groups like - and 26 per cent hate. In the past, that dislike would have killed the design while it was still on the computer screen. Today, such a whiff of controversy is just what the carmakers are looking for. Good is bland, bad is good, and suddenly instinct is cooler than logic.

Consider: in recent years, the globalisation of the car industry meant that all cars came to look much the same everywhere. The aim of the manufacturers was for the greatest number of people to be unoffended by the look of the product. This avoidance of risk was achieved through styling "clinics" and focus groups, and meant that national and marque differences were ironed out. Weird French cars ceased to be weird, Japanese cars stopped being ugly, the Americans toned down their once incredible styling in the name of international sales, the British gave up making their own mass-market cars altogether, and invited everyone else in to do it for them.

This homogenisation meant that our streets became dull. Stylistic eccentricity, as represented in vastly differing ways by the Citroen 2CV and the Austin Allegro, was right out. So were engineering variables. The handling and performance differences between makes all but vanished. As with washing machines and video recorders, there was an appearance of endless choice at each price level that was in fact no choice at all. To put it another way, the car market became like architecture's dogmatic modern phase, where you could have any building you wanted so long as it was a box with a flat roof. But now the world's motor magnates, like the world's architects, are discovering the joys of pluralism. Retro cars, cute baby cars, pig-ugly cars, even modern cars - they're making them all, along with the kind of open-top roadster that, a few years back, everyone told you would be legislated out of existence.

This marketing shift began a few years back, when Ford - previously famed for the anonymity of its products - decided to produce what seemed an outrageously ugly new big car, the Scorpio. It was bug-eyed and strangely proportioned, but you noticed it. Today - so far has the market moved - you scarcely notice the things any more. Ford then quickly restyled its bland world car, the aptly-named Mondeo, to look rakish. All of Ford's new cars since have adopted more or less radical styling, culminating in the ironically-named new mid-range car, the Focus, which looks like a student design project of ten years ago from the Royal College of Art - extreme then, acceptable now. This sudden and complete change of emphasis by the world's biggest motor manufacturer caught others on the hop - such as Citroen, once leaders in outré design, whose cars had come to resemble old-style Fords.