Just to give a little bit of background on some of this...
I was in a previous life involved in the motor industry and was involved with people who conducted the testing for the economy and mileage figures quoted by motor manufactures in the brochures. Everybody and I mean everybody in the industry has known for years and years that the numbers published in the brochures are complete nonsense. I'll explain why:
When the testing on a vehicle for MPG was conducted the car was effectively stripped back to its bare bones. The wing mirrors and door handles were removed. All of the trim and extras and accessories were removed. The seats were changed for light weight versions along with the tyres etc etc.
Anything and everything that could be slimmed down or removed to reduce weight and wind drag were taken to the absolute extreme.
Therefore the numbers quoted in the brochure are effectively totally fictitious on every level.
As I say EVERYONE in the industry was aware of it. The general public have and are being lied to on a daily basis regarding such issues.
It is a scandal of the highest level but no one appears to give a shit.
The thing there is that the EU authorities allowed them to do all of those "cheats" for the fuel economy tests, so everyone did it and followed the regulations therein. That they were complete nonsense is one thing, but everyone's figures were produced on the same basis, with the arguable exception of Mazda, who made a selling point of trying to produce vaguely realistic results (much good it did them). Whereas the VW diesel scandal was about cheating the system deliberately, not abiding by lax rules.