It's a law in Sweden (or Scandinavia) requiring rear fog lights. They (Volvo) also invented the three-point seat belt. The Europeans have forgotten more about automotive safety than Detroit or the US Federal Government will ever know. As for the Japanese, they simply wait for the Europeans to invent and test something and then copy it. That's why the for R&D on a Lexus is next to nothing.
I simply don't understand why Mercedes doesn't collect patent rights on their safety inventions.
BTW, only Volvo and Mercedes send teams out to investigate accidents involving their products.