It´s been said of radio that its advantage over other media is that the pictures are better.
This is generally true but when it comes to car advertising it is not. Radio ads can´t hope to convey the visual impression of a car, its most important attribute. Instead they are left to handle other aspects which can be presented verbally. These might include news of special offers and to point customers in the direction of dealers. They might serve to tell listeners of the arrival of a new model but other media must handle the rest. One advantage they do have is that they have a kind of captive audience and they contact the biggest audience for radio, drivers trapped in their cars.
“Every credit application will be accepted” was a favourite line of a set of ads for a chain of dealers who advertised on radio when I lived in the US. That sounded good but wasn´t actually much of a promise. Of course they would accept the application but might not actually give you any credit. They merely wanted as many people to come and look at their car as possible.
Another car ad I remember drew on a reference to Tales of the Unexpected, a series of one-off mystery dramas that ran in the 1980s on ITV. The ad was for the Peugeot 405 estate and the pained and forced trope was that the car was an estate but didn´t look like one (which in reality it did, very much so). Two actors gamely got through their script and listeners were left to wonder why Peugeot were so desperate to deploy this rather lame schtick.
I haven´t heard so many radio ads in recent years as my car hasn´t got a radio so I have no idea of the state of the art. Are radio ads still stuck telling us of the great deals on trade-ins? Do they still have to find awkward ways to make lists of features interesting? Perhaps the very difficulty forces some creative to new heights of originality but maybe there are still copywriters producing stale versions of Mastermind where the chosen subject is the car in question. Or it´s just a voice-over artist announcing the arrival of the new Mazda 323 with a 6 year guarantee and that a test drives are possible at your local Mazda dealer.
Cars are visual and tactile and radio is not. That´s why radio ads have not become fondly remembered as fun, disastrous or effective. Brochures can be kept. You Tube provides a home for grainy home-recordings and old magazine ads can live for ever to be scanned and uploaded or traded on eBay. The radio ad is the poor relation.