I had a similar problem importing romaniaRomania and hungaryHungary sql files bunbut not in the case of usUS imports. The problem was that some segments were not inserted because of an encoding problem. Solved this by changing the client encoding to UTF8 in the psql console. The code I used looks like this:
mydatabase-# \encoding UTF8
mydatabase-# \i d:/countryname_2po_4pgr.sql