So how easy was it for VW to fool the EPA in the USA and California Air Resources Board for so long

Well when you actually look at what is involved in their Diesel emission test

http://www.smogcheck.ca.gov/pdf/DieselFlyer_final.3.pdf

See if the MIL is on?
Visual inspection of emission components?
Visual smoke test?

So the whole test is down to a human just giving a visual inspection

Hence the initial test to let the vehicles being sold in the US is stringent (using dodgy software) after that they are home and dry

That is until some automotive nerd in a University decides to do a real world test with some proper emission equipment.......and blows a gaping hole in their own emission testing practices and VW

At least in the UK we do a test to check at least one of the harmful particulate components, but not the VERY harmful NOx

So in real terms I cannot see anything being done about affected vehicles in the UK

I service quite newish vehicles, even when the doors are all open and I have a newly serviced diesel ticking over it starts to make my eyes water and soreness in my throat.......can you image a street full of these ticking over in a busy London Street!!

Lets face it, Diesel is not a clean fuel no matter how much software you throw at it or bolt on emission devices

I don't believe VW will be able to fix the problem with updated software, just have to put up with the pollution till the end of their life......reducing the NOx emissions to such a low level is just going to strangle performance

Peter