It was said that if front ends were safe in 40mph shunts, they would endanger life in nose-to-tail shunts. By that logic, cars should be made of papier mache

The car industry doesn't so much shoot itself in the foot when it comes to PR, as blast both legs with sub-machine guns. This week's safety tests on seven superminis, which castigated the Rover 100 and praised the latest Fiesta and Polo, were a noble and honest attempt by the Department of Transport, the RAC and the AA to shed some light on car safety, an issue which motor makers' ads have done their best to obfuscate. And instead of making sensible comment and admitting that, yes, some cars are safer than others, and that much still needs to be done (though past improvements have been great), the various motor-industry PR dimwits who surfaced cried foul and tried to pour scorn on the whole worthy enterprise.

Individually, most car companies have effective PR, but when it comes to representing the motor industry as a whole there is a notorious level of incompetence. Past PR "coups" include hiring Coventry Cathedral to commemorate the centenary of the car. But the excuses that the Society of Motor Manufacturers and Traders (apologists and publicists for the car industry) and Rover, whose incompetent 100 supermini was castigated in the crash tests, trotted out this week plumbed new depths of disinformation. They whinged that the crash tests were done at too high speed - at 40mph, whereas new official crash tests will be done at 35mph. They whinged that the crash tests performed in the study were unrepresentative. And one SMMT "publicist" even maintained that, if car front ends were designed to be safe in 40mph shunts, they would be so tough that they would endanger life in nose-to-tail shunts, because the tails of cars would cave in. By this logic, all cars should be made out of papier mache.

In fact, this week's crash tests on the Rover 100, Ford Fiesta, VW Polo, Vauxhall Corsa, Renault Clio, Fiat Punto and Nissan Micra were not all bad news for the car makers. They showed that the newer cars - the Polo and the Fiesta - fared best. Ergo, cars are getting safer. John Bowis, minister responsible for road safety, said as much at the press announcement.

The Rover 100, an old Metro with extra chrome-work on the outside and wood on the inside, is almost 17 years old. It was designed well before car makers used computers properly to optimise strength, and as such will fold worse in a smash than newer, more advanced cars, such as the latest Fiesta or new Polo. This finding will surprise nobody, least of all Rover.

The 100 is still on sale purely because Rover has not had the resources to replace it, and no amount of glamorous Rover PR bumf (limited-edition Rover Kensingtons and Rover Knightsbridges, complete with trendy girl- about-town Sloaney owner etc) should kid you otherwise. Although it was not tested, it is a fair bet that the Mini, which is even older than the Metro, would have done even worse. The Rover 100 is an old, inadequate car that should have died years ago. These latest safety findings will , it is hoped, speed the death process a little. (The Mini is at least fun, even if I wouldn't want to crash in one.)

The Metro was the smallest car tested. I remember, a few years back, asking the safety chief of a big car maker which was the safest model of all, expecting him to proffer the names Mercedes and Volvo, whose reputations in this field are brightest. Instead, he simply answered: "The biggest. You can't overcome the law of physics. A two-ton car will always do better in a crash than a one-ton car."

Air-bags, side intrusion bars, crumple zones, seat belts etc all do their bit, and are part of the reason why cars are getting safer and why fewer motorists die every year. But, sometimes, they are fitted as much for marketing reasons - to imply safety and help to sell more cars - as for genuine safety reasons. The safest cars are not necessarily those with the most safety add-ons, as the ads imply.

So what are the safest cars? Disgracefully, nobody is really sure. But the new tests, launched this week, will help us to find out.