The whole AdBlue(™) thing seems like a patch up job to me. Apart from the EPA wanting to have all vehicles obeying one standard is the saving of the amount of NOx from a few '000 expensive diesel M-Bs going to save the planet ?
No it isn't but that's not the US EPA's concern. As fuel costs rise, the trend that has already occurred in Europe will start to happen here. There one out of every two new cars sold is a diesel apparently. If we in NA even reach the 1 in 5 or 1 in 4 market penetration level, air quality in most urban centres will be the worse for it unless you set some pretty stringent emission controls.
I like diesels except for what I see (particulate) and smell (more particulate). I was driving behind a new M-B CDI tonight and I could smell it after having left the stoplights. And this is in my car that is equipped with a micron cabin air filter. When I follow behind a TDI leaving lights, not only can I smell those as well, but I can see the soot out the pipe when under load. This is as clean as technology can get them? They are still sooty little stinkers.
Very few "gas" powered cars can my nose smell or eyes see in the same situation as above (unless it's a Chrysler with the 3.0, or a Ford with the 4.6).