I can,t think of any diesels made and sold since the mid 1990s would throw enough soot to be a problem if the engine is in good health. If you look inside the tail pipe of the newer 2008s and newer,,, there is almost a white ash inside the pipe they burn so clean..
Now on the other hand,, the kids that tune up there diesels with over sized injectors and fog raw smoke out the back to show off would be different story.. But I can,t picture anyone from this group would throw $1000s of dollars to just blow smoke..
it is not that the newer trucks run so much cleaner but that the particulates are trapped in the dpf