Well, the propane truck driver may have just checked to confirm that the "pole fuses" (long ceramic tubes with fuse strips inside) were blown at the head of the driveway. If they were, and don't try this at home if you don't know what to look for, it was perfectly safe to drive over the lines. Of course, there's the other end of the line as well, the one hooked to my mother's back-up generator which if it didn't switch the outgoing line off automatically when it comes on line would have also blown "Propane Bill" straight up to Heaven.

Cheerily,
Charley Noble