Rusty Cars Probably Not As Safe As New Ones, Says Surprising Study

If you’ve ever been driving around in a car you know is hellishly rusty underneath and wondered exactly how safe you’d be in a crash, you’re about to find out.

Well, actually, you’re not, because while a few old, rust-eroded cars have been crashed at the UK’s Thatcham Research Centre on behalf of two safety-minded Swedish companies, the results are pretty inconclusive.

The initial idea from insurance company Folksam and a homeowner’s organisation called Villaägarnas Riksförbund was to show how much less safe a rusty old car is than when it was new. Indeed, the headline Villaägarnas Riksförbund used in its press release states that, in a crash, you’re 20 per cent more likely to die if your car is badly rusted. However, it’s not that simple.

Two MkV Volkswagen Golfs and two MkI Mazda6s, all from the mid-to-late-2000s and definitely at least 10 years old, were crash-tested for frontal and side-impact safety. The results were compared with the cars’ scores when these models were new. Surprisingly, the Golf barely lost any ground on its as-new performance, scoring 32 points instead of 33. The rustier Mazda dropped from 26 points when new to 18.

The Mazda’s figure is where that ‘20 per cent’ claim comes from. As noted first by Jalopnik, though, the study does say that it’s by no means certain that any other rusty Mazda6 would behave in exactly this way. Also, much of the rust was ultimately judged not to have impacted the car’s front- and side-impact safety at all.

On the other hand, the way the Mazda has ‘de-bonded’ in the places where its rust is particularly heavy, where chassis parts and the floor have separated, indicates that driving a car with rusty guts might not be all that sensible anyway, the bottom line being that you simply don’t know how well it will handle an impact.