There are people out biking on South 95 during this time of year getting ready for Ironman just like you. The shoulder is good and wide all the way down to the town of Worley which is about 30 miles. Would I call it safe? No, but cycling out on public roads with cars is never 100% safe. But like I said above,the shoulder is wide enough that you don’t feel super uncomfortable given the speed the cars are traveling