In May a lot of that road on the south side of the lake was tore up. They didn't just tear up one lane for rebuilding...they tore up both lanes! It will be great once they finish, whenever that is.
They have been rebuilding that road in sections for several years. Probably no way to know which sections will be done or if they plan to do all sections. It was a narrow road with no shoulders. Now the sections they have done are wider and have shoulders. But you still have to go through one very narrow town where it does no appear possible to widen it. I have read posts saying there could be a periferico/librmento built on the lake side of town but we have seen no indication of that. The construction areas are maybe 5 miles long each time they do another section. Slow going and our motorhome got very dirty. But we survived. Surprisingly the road from that road up to Mazamitla was done first and has been done for years. Many roads all over Mexico have been upgraded in recent years - things have gotten better on many back roads.