rSAP and live traffic
rSAP is in theory good, because the car's infotainment system is linked via BT to a good GSM antenna, hence better network reception than that of your phone (depending on where your phone is placed in the car). But rSAP - as its name suggests - uses your phone's SIM card to access the network and - this is the important bit - it disables the network connection of the phone handset.
This means that TT live traffic will show as unavailable!
Solution is to force the phone to connect as HFP, not rSAP. Various ways to do this eg in the setup, Android will normally ask for permission to link the SIM card to the BT device, so denying this will force HFP. Might also be able to change from rSAP to HFP in the infotainment menu.
Hope others find this useful