Carriers have mapping independent of networks. Drivers keep personal GPS too. You would lose traffic and road conditions, I guess, but nothing proper trip planning wouldn't cover.
Do they? I know there are a lot of old units out there but I figure people would have tossed them.
At least I’ve found Waze has been pretty good at starting off with wifi and loading the map of the whole journey after coverage was lost with some resilience for stops/detours.
