Q: Notifications (like text messages) to my iPhone are inaudible when it's connected to the bluetooth in my car (no headset applicable); has this issue been resolved?

Ask your car manufacturer if they have resolved the issue with their bluetooth implementation. It is NOT an iPhone issue.

This might be an iPhone or a car issue or even Bluetooth protocol design issue depending on where the fix is done to make it work.

I have an F250 and when Bluetooth is connected (always) and I have selected the Bluetooth connection in Media on the radio as the input and I am listening to music on the phone (or not).  Notifications come through the truck speakers.  The key is that I have selected Media, Bluetooth stereo (phone) as input.  This works fine if I am playing music from the phone.   The problem is that I change to Sirius radio which is what I mostly listen to when and then there will be no notifications through the truck.    Assuming that the iPhone is still trying to send notifications to the truck while I am tuned to Sirius, then it would go good if Ford could pick up whatever notifications come from the iPhone and pass them through the speakers.  I don't know if Ford can distinguish a notification from streaming music - don't know enough about the Bluetooth spec to know what is and isn't possible.   If Ford (or other auto manufacturers) cannot distinguish a notification/alert from streaming music/audio to pass through the speakers then maybe Apple could work on the phone and give us an option to pass the notification/alert through the phone speaker as usual even when the phone is connected to the vehicle for calls and not being used for music.  Maybe Apple could even make the software smart enough to pass the notification/alert to the truck speakers when music is streaming to the truck or while on calls (active audio stream) and for all other notification/alert, send through the phone speakers.  I rely on alerts and then realize I miss them and notifications from VIP list all the time because of this.  Sometimes I just turn off the Bluetooth when I am expecting something important from someone.  I will post to Ford forum as well.  Either Apple software engineers or Ford software engineers should understand the issue that I have described and one or the other might be able to put it in the queue for modifications