I had always assumed most patent applicants knew about the Patent Prosecution Highway (PPH) and were taking advantage of it.  Evidently not.  I just attended a patent conference where the speaker suggested that not many people are using the PPH.  The speaker indicated that the patent office wants this program to succeed.  He showed statistics that the allowance rate triples if you take advantage of this program.  In that sense, it is similar to Track 1 expedited cases that I mentioned in another post.  If you are foreign filing on cases and you want to push you US case through, considering using your foreign cases as a basis for the PPH.  It’s not quite as good as Track 1, but in my experience, it’s close.