Not all crash test stars are created equal

Tuesday, 15 October 2019

ANCAP has launched a new campaign that compares the relative safety of an older car and a near new car in a crash. The results speak for themselves.

Safety sells these days and rightly so.

It sells mostly on the strength of star ratings, which should in theory make individual scores easy to understand and easy to compare. But this is where theory and practice part company, because that simple star-rating system is not simple at all.

For a start, it's not a single system. The star ratings you're probably most familiar with - because they're often used in advertising - come from the Australasian New Car Assessment Programme (ANCAP), or perhaps its parent organisation Euro NCAP. These are the ones endorsed for New Zealand by the government and the Automobile Association (both are funding members).

Previous-generation Suzuki Swift has been the subject of some star-rating confusion.

ANCAP tests are for new cars and they're done using smashing and a fair bit of science, in a laboratory. So they're consistent and a really good way of comparing similar-size models. Most agree that the rise in importance of independent NCAP testing has really forced carmakers to raise their game in terms of safety. That's a good thing.

**READ MORE:

The Mansplainer: crashing at the kerbside, but looking at the stars.

* What does ANCAP do and why do we need it?

* Proposed ban on 'unsafe' imports makes no sense

* Updated Ford Mustang safer, but still only three stars

* The lowest crash test score in a decade**

But the problem for us consumers is that the tests are always evolving and getting tougher all the time. So you can't really compare ANCAP star ratings from different years unless you've delved into the relevant testing regimes for each period. It's worth bearing in mind because it means a new-car four-star rating from this year isn't necessarily worse than another car that got a five-star rating five years ago.

That's why ANCAP started date-stamping its crash tests a few years back. It's kind of like a Best Before for those safety stars.

You've probably also heard quite a bit about Used Car Safety ratings, which are a different thing again and no relation to ANCAP. Although they are still endorsed by the government and they do still offer star ratings.

The Used Ratings, for cars over seven years old, are harder to fathom because they are based on real-world road crash data from NZ and Australia (over eight million of them). The exact methodology is bit mysterious, but according to the programme the ratings are 'adjusted for factors such as driver gender and age, type of road user involved, speed limit at the crash location, number of vehicles involved, crash configuration, and year of location of crash'.

Used Car Safety Safety Ratings are also great in theory, although there have been some inconsistencies in the star ratings. Most famously, the 2011 Suzuki Swift - a five-star car under ANCAP testing when new - only gets one star under the Used Car Safety Ratings. Or the Mazda2 from 2007-14, which was another five-star performer when new but only gets two stars under the real-world Used Rating system.

I'm not saying ignore safety ratings. Just be aware that the stars don't shine as brightly and consistently as we'd like sometimes.