This is the problem with riding in shoulders and bike lanes, drivers don't realize they just end. When there is a big shoulder like that I tend to feel more comfortable staying in the lane (Maybe ride a little closer to the line since I have room to slide out if i feel like someones gonna buzz me, but still holding the lane) just to be consistent about the fact that that is where cyclist are supposed to be
a shoulder or bike lane is just a glorified sidewalk (thats more for the drivers peace of mind then the rider), people still don't expect you when there turning.