My feeling is this - yes, drivers face many distractions and are quite irresponsible and in some cases, downright dangerous and worse, criminally negligent to the peril of innocent cyclists.  That being said, the roads must be shared, by all vehicles as designated with signage, policy, posted speed, etc.  The singing highway is one of two of its kind in the United States.  It's an amazing feature that actually adds quite a bit of character and charm to an otherwise fairly boring roadway.  I have friends from out of state who have noted it on social media, it's now part of the Rt 66 experience for the numerous of venturers that explore Rt 66 and happen to come upon it; it's a really cool thing!  It is also a fairly short segment of the roadway.  To call for its removal, to me, is quite misdirected, and fails to recognize the primary issue - that of careless drivers.  

Now, to have the GABAC write a letter, well, look what it has spawned - a letter to the editor of the largest newspaper in the state, basically slamming the cycling community as a bunch of wackos.  As a cyclist, I don't appreciate this.  I speak out of experience of having been on the GABAC in the past, and I can attest that it is a delicate balance to reconcile the relationship between cars and bicycles.  The cyclists have legislation behind them these day, and some times even that is not enough