Re: Something I have long wondered about...
...is why the other perpetrators are being constantly and consistently ignored in this. VW were only the first ones being caught, and were the first ones by pure chance--the road-test procedure used to check on-road emissions just happened to be tested on a VW Golf Diesel first, because the car was at hand. It could just as well have been an Audi A3 (OK, same company), a Honda Accord Diesel, or even a Jeep Cherokee.
You are conflating two issues. No diesels meet emission regulations in real world testing. That has long been known in the industry and is now known more widely. But there was no cheating going on, it is just a factor of poorly designed test regimes. Or rather - far too well designed test regimes that in seeking to give repeatable results became unrealistic. Take any BMW or Honda off the street and it will pass the test despite being dirty in real world conditions.
But what VW did was go further. Because the test is so predictable the cars were programmed to recognise when they were being tested and switched to an engine map that would never otherwise be used. If you tried to drive an Audi in that mode on the road it would be gutless to the point of being undrivable. Because they then didn't need to concern themselves with passing the test Audi engines on their real map became far worse polluters than the equivalent BMW or Honda.
The two situations are radically different and we should be grudgingly thankful to Audi because without dieselgate it seems unlikely to me that the first situation would be getting addressed. The tests would have just gone on getting tighter and tighter and less realistic very time. What we need are tests that are numerically less strict but applied all driving situations and so far more beneficial overall.