Originally Posted By: javacontour
Sure, but weren't we at that goal in the 1990's? The legitimate question is when do the incremental benefits no longer justify the costs?
Frankly, IIRC, NOx is more about acid rain, not about smog. And it was only a problem in certain areas. Wouldn't it make more sense to allow a vehicle to pick and choose emissions standards based on it's location? If in a congested urban setting, a more strict standard. If in a sparsely populated area, a more lax standard in favor of increased fuel economy could be implemented. The car picks the standard based on GPS readings.
If it can't determine via GPS, the strict standard is the one the ECU chooses.
But one-size fits all solutions really don't benefit all. They benefit a few. But all of us pay.
Makes perfect sense. They could also use an FM radio subcarrier to announce it's an extra-bad day in the broadcast region and please detune.
Saving CO2 is more of a country-wide if not global goal, and clean, lean diesel when its NOx isn't a problem is great for this.
For all we know the EPA defeat device could be a GPS that detects the test centere. (Though Jalopnik posits that it's the rear wheel speed sensors at zero being strapped down on the dyno.)