&quot;Its not clear this [lab-vs-road discrepancy] is any kind of problem.&quot;<p>I agree with what you said, except this.<p>Clearly these NOx emissions are a problem, because they cause smog (like ozone), which is a health hazard.  The city where I live has too much ozone for many days of the year, for example.<p>Unless this problem can be controlled, vehicles like these should not be sold here, and people will have to find other options, or technologists will have to develop better cars.