So, the real moral here is that Volkswagen took advantage of the fact that our emission standards basically trust the cars own on board diagnostics to determine if they pass emissions...<p>CA, at least, uses the BAR-OIS inspection for diesel cars, coupled with a "visual inspection" to make sure that the car does not produce visual pollutants. Effectively, this means that the software reads whether the car is passing from the OBD-II port in the car, and then, as long as the car has the necessary parts (Exhaust recirculator, catalytic convertor, etc) then it passes.<p>It would not surprise me to find out that more than just VW have these kind of issues. Effectively, we don't actually verify with any instrumentation whether the emissions are within spec.<p>Sure, VW may have duped the system on purpose, but, the fact that this has gone on for <i>years</i> has to weigh in a bit on a critical mind. Our tests don't work very well if this stuff can go on this long.<p>___<p>Of course, it is also trivial to find an inspection location that will pass almost any diesel vehicle, if you know where to look. For any interested parties, try googling "diesel exhaust delete" or some similar query for any number of Ford f-350s, Ram 2500s or any other large turbo diesels. This basically consists of taking a saw, and cutting out the EGR, and some other flow restricting parts of the exhaust to increase exhaust flow, typically done in combination with a chip/turbo map.<p>The results can be significant. A person I know got a fairly significant bump in both power and MPG at the expense of needing to carefully plan how to pass emissions tests. The main question that weighs in is whether it is better to pass emissions and get 13-15mpg, or to fail emissions technically, but get 24-26Mpg with diesel. Those are real numbers with a 2008 Ram 2500.<p>I think this VW thing should spark a larger conversation about how we measure emissions in the first place, and what cost the emissions passing imposes.