What is the NTE test? A technical description can be found here, but in brief, the NTE test places limits on exhaust emissions during real-world highway-type driving. The NTE test does not place any limits on emissions during other kinds of driving, such as low-speed or low-load operation, urban operation, or transient driving (lots of different speeds and accelerations and decelerations). And because U.S. regulations rely so heavily on the NTE test, they don't effectively address emissions in those conditions. Unsurprisingly, heavy-duty vehicles on the road in the United States today have very low emissions during highway driving and very high emissions during urban driving. In fact, as diesel trucks exit a freeway to enter into a heavily populated area, the harmful emissions in their engine exhaust increase by an order of magnitude. Please click here to view the full press release. SOURCE: ICCT