Crash Course

Andrew Noakes reveals the untold story behind the Euro NCAP crash test ratings.

By Andrew Noakes / Thursday, 28 July 2005 / Loading comments

Brussels may be the centre of much Euro-absurdity but it's also the headquarters of an independent European body which has been doing a lot of good over the past few years. Since 1996 Euro NCAP – the European New Car Assessment Programme – has been subjecting new cars to crash tests and publishing the results in the form of star ratings. The most recent results were announced at the end of June. Two good things result from all this destruction: car buyers can make more informed choices, and car makers are encouraged to design cars that better protect us in accidents.

How it works

Mercedes SLK

Mercedes A-Class

BMW Mini

Fiat Seicento (one of the worst)

Renault Modus

There are four Euro NCAP tests, which are carried out by a number of European crash test labs including BAST in Germany, UTAC in France, TNO in the Netherlands and TRL, the Transport Research Laboratory, in Berkshire. The first test is an offset frontal impact at 40mph, where the car hits a deformable aluminium barrier with a 40 per cent overlap on the driver's side. That's roughly the equivalent of two identical cars colliding at 34mph. Next come a pair of side-impact tests: a trolley with a deformable front end is towed into the car at 30mph, and the car is propelled sideways into a rigid pole at 18mph to simulate an impact with a tree or telegraph pole. Finally, pedestrian safety is assessed in a 25mph collision with the front of the car. Where appropriate the car will be tested with manufacturer-approved child seats fitted, one for an 18-month-old and another for a three-year-old.

'Injuries' sustained by the crash test dummies are translated into a points score, and the front and side impact scores (out of a possible 34) are added together. Extra points are awarded for approved types of seat belt reminder systems. Provided the scoring is reasonably even between front and side tests, the total is then turned into a star rating: 33 points or more wins five stars, 25 to 32 points gets four stars, and so on. Star ratings are awarded in a similar way for pedestrian safety and child safety.

Interpreting the results

But while the star ratings may look like an easy way to tell whether one car is safer than another, they don't tell the whole story and they need to be interpreted with care.

For a start, the cars tested by Euro NCAP are divided into nine groups by size and type – superminis, small family cars, large family cars and so on. The star ratings are only comparable within each group. Bigger, heavier cars will always survive better in any given accident than smaller, lighter ones, so while the Mini Cooper and old-shape BMW 5-series both score 25 in the front and side crash tests, the 5-series will cope better in most real-world accidents. The highest-scoring car so far tested is the Peugeot 1007, but it's likely that several big saloons and MPVs would be safer places to sit simply because there's more metal between you and the accident. There are more limitations when it comes to child safety: the Euro NCAP ratings apply only to the single specific combination of vehicle and child seat tested. A different child seat, or the same seat in a different vehicle, could produce very different results.

BMW Z4

Mazda MX5 (pre-facelift)

The simplistic star rating can also distort the relative merits of different cars. For instance, two cars with the same star rating can offer different crash performance: both BMW's Z4 and the now-superseded Mazda MX-5 are 'four star' cars, but the Z4's front/side impact score of 31 comfortably beats the older MX-5's score of 25. Conversely, two cars with different star ratings can offer quite similar protection. Mercedes added a seat belt reminder to its C-class which bumped it from four stars to five, even though the actual crash performance of the vehicle didn't change. The BMW 1-series and new VW Golf are two more cars to benefit from seat belt reminders, both achieving five stars instead of four as a result.

Another problem, and one which can only get worse, is that the tests are evolving all the time. New tests have been added since the programme began, and methodology has changed as the cars and the tests develop. So some older results, particularly those for pedestrian safety, are difficult to compare with the latest round of tests.

The newer, the safer

Even so, the Euro NCAP results are the best available way of assessing new car safety. Studies in Sweden have shown that, in general, cars with higher Euro NCAP ratings offer a better chance of avoiding serious injury, so it certainly makes sense to consider the ratings when you're choosing your next car. Better still, look at the points scores – all of which are published on the Euro NCAP website – to see the real differences.

Whether you consider the data or not, the good news is that the Euro NCAP programme is encouraging car makers to design safer cars. Look through the results and you can see clear improvements between older cars and the new generations have superseded them, all of which is the result of careful safety engineering rather than simply building stronger cars.

Smart car

Strong, unyielding structures stop suddenly when they hit something, but their occupants tend to carry on moving until they collide with some part of the vehicle, causing injury. Most modern cars use the 'safety cell' concept invented by Mercedes-Benz engineer Béla Barenyi in the 1950s, where the passenger cabin is strong but the front and rear of the car are designed to crumple progressively, dissipating the energy of the collision. But the tiny Smart Fortwo actually turns this principle on its head: too small to include worthwhile crumple zones, it instead has a strong outer skeleton which is designed to activate the crumple zone on the other vehicle in the collision.

Euro NCAP is now extending its advice into the field of accident avoidance, recently recommending that consumers choose cars fitted with electronic stability control. That's likely to become a more common standard-fit now that it has such high-profile backing.

Whether or not you take any notice of the tests (which in any case only cover the most popular models) or listen to the recommendations issuing from Brussels, you're likely to benefit from the work of Euro NCAP. All cars are safer than they were, and future cars are likely to be even safer still. And that has to be good for all of us.

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