What ever happened to the Diesel emission regulations?

Graph of Emission standards

And, when will they roll out Tier 5 (in the United States) and Stage 5 in Europe?

We came across a really useful graphic prepared by Cummins. It shows the roll out of the various emissions standards across the various horsepower ratings and in the major adopting markets of the US, Europe and Japan.

The “Tier 4 Final” standard is fully implemented in the US and nearly so in Japan. The Tier 5/Stage 5 emissions regulations have not been written into law in either Europe or the United States. However, it only makes sense for engine manufacturers to begin preparing for what will probably be under consideration in 2016, and required by law by 2019. The reported scope of Stage V in Europe will differ somewhat from all the regulations that came before. Previous regulations exempted engines of less than 24 horsepower. Stage 5 will likely cover all engines regardless of horsepower. If Stage V and Tier 5 go forward as anticipated, a particulate filter will likely be included on every diesel engine, large or small, stationary or mobile, by 2020. We will have to wait to see what is announced.