The Euro NCAP crash tests help us understand which cars are the safest, but what do the scores mean?

The European New Car Assessment Programme (Euro NCAP) crash tests have been running since 1997 and have become the standard way to judge a European car model's safety.

In 2009, Euro NCAP added an overall score to its testing regime, giving an at-a-glance mark out of five stars for a car's safety performance.

To work out how safe a car is, though, we need to look a little more closely at how the scores are calculated.

Scores on the doors

There are four areas tested by Euro NCAP:

Adult occupant.

Child Occupant.

Pedestrian.

Safety Assist.

Each is given a score out of five stars, with five being the target for most companies.

A series of crash tests carried out by Euro NCAP helps determine the score each car is awarded, but important points are earned for standard equipment fitted by the car's manufacturer. The more equipment a model comes with as standard, the better its chances of scoring well, although it must still meet the required impact protection standards to score highly.

A car with a lower score may do well in the passive crashworthiness tests but may not be fitted with as much standard safety equipment as a rival model. As a result, two cars that perform equally well in a crash test might end up with different overall scores. This is where digging into the EuroNCAP results breakdown helps.

For each of the four areas, the car's performance is also given a percentage rating. This allows you to compare cars with the same overall star rating to decide which performs best in which areas – and which is best suited to your needs.

Star ratings explained

With the five-star rating system used by Euro NCAP, any car with a three-star rating or above offers average to good occupant protection, but a three-star car does not offer crash avoidance technology. This is to recognise that safety and collision avoidance technology has moved on a great deal since Euro NCAP first conducted tests.

Back in 1997, few cars had side airbags as standard and ABS anti-lock brakes only became mandatory on all new cars in 2004. So, the Euro NCAP tests have had to evolve to reflect the advances in safety equipment and set the bar ever higher.

As a consequence, the biggest changes to the Euro NCAP tests recently have been for safety assist. Where once this section of the tests centred mostly on ABS anti-lock brakes and then ESP traction and stability control systems, it now covers speed warnings, lane keeping assistance and automatic emergency braking.

To the future

More new cars now come with these systems as standard or as optional equipment. When they become the norm, Euro NCAP will recalibrate its star ratings to differentiate between the performance of each car's system. In doing so, Euro NCAP will set even higher standards for car-makers to meet if they want a coveted five-star rating.

Some tests will remain the same, though, as they are the ones that replicate real-life collisions for the car's occupants and pedestrians.

The good news is that Euro NCAP has helped raise safety standards for all cars and is continuing to push for ever greater safety, which is good news for car buyers and all other road users. Whether it will also drive the move to automated cars, with or against public will, remains to be seen.