Matthew Avery, Euro NCAP board member and chief research and strategy officer at Thatcham, told Autocar: “Every few years, Euro NCAP raises the bar by introducing new tests which either exploit new technologies or lift the hurdle to make manufacturers do better. If everyone is five-star, we need to lift the barrier."
As a result of these alterations, he explained: “When we first tested the Zoe, it did reasonably well and had all the elements you needed back then to get a reasonable score. But if you've still got the same design 10 years later, you aren't going to score as well.”
"The Zoe was launched in 2013 and received 5 stars with Euro NCAP protocol at that time. The Euro NCAP protocol has since 2013 undergone five changes. With the same equipment, a model can lose up to two stars in each protocol change.
I was not aware how quickly and dramatically the tests change, it makes comparison between different models almost useless unless you read through entire test protocols.