one of the prime reason for low voter turnout is because of the dominance of the democratic party and the lack of viable candidates from the repubs.  hence, may repubs felt that it was not necessary for them to vote and the rail issue has been the major issue for the last 3 elections and now with rail maybe half complete, many felt that rail will prevail in some form, causing many to lose interest saying that what ever will be will be.  for the general election the vote rate should increase as many of the races will be more meaningful.  also, because the primary election is a closed election, many democrats or repubs feel that whatever candidate of their party will win so there is no real need to vote as they can vote in the general, which in most cases will elect someone where there are multiple party candidates.