I've never had to call an ambulance, and the only person I know who has, is my f-i-l in rural Poland, which provides another bit of anecdata about the uselessness of various location-reference systems. The post code there refers to the whole of the nearby small town. The incident happened in a village a few miles away, and on the edge of that village. There are no street names - the postal address uses the village name plus a house number. Strictly speaking, the village name for this part of the village uses a suffix, but no one ever refers to it that way in practice. Nobody in the village knows any house number apart from their own, either, and because the whole village is numbered in one continuous sequence, and from time to time new plots get developed, they aren't necessarily sequential. None of the houses actually have a number displayed, either. Several times I've witnessed delivery drivers ask people who've spent their whole life in the village,
"Where's number 123?"
"I haven't a clue. Who lives there?"
"Szczygiel."
"Oh, that's the white house with the green roof and the blue door, next-to-last before the forest."
But the ambulance, of course, comes from town and doesn't know the locals. Presumably there is a grid reference system, but I've no idea what it is (in fact, AFAIR local maps only have lat and long marked - but in any case, people in the village won't use those, because they have no need to).
Add to this a paucity of surfaced roads, and perhaps it's no surprise that when the neighbour had a heart attack, the ambulance took thirty minutes to travel 7km. By which time the poor man was dead.