This sounds like us.
MDT "get route", then paper map book, then personal GPS units.
Not sure if its just, but we've had a constant problem with personal GPS units taking crews wrong ways, less than ideal ways or not having the roads programmed. We have a policy about this now that says personal GPS is a last resort and if not used as such and there is a response delay caused by an inaccurate personal GPS the crew will face discipline.
Not an issue with the paper books and our MDT/CAD.
Exactly. Personal GPS can cause wrong route and will face discipline. So either follow blue line on MDT or Map book.