It's not about "sensor fusion" in the usual sense - no one is proposing to compare street signs to Google maps to detect map errors. Rather, it's about keeping

It's not about "sensor fusion" in the usual sense - no one is proposing to compare street signs to Google maps to detect map errors. Rather, it's about keeping the same multi-level navigation strategy people used before Google maps. Remember the offline planning? You may plan the route by the map or write turn-by-turn directions, but as you follow them you should be watching for overall road conditions. Bad traffic jam? Street that seems suspiciously steep? Road closed due to construction? Rain damaged road? There were no expectation of map being always up to date, so you always needed to be aware. For some reason, some people lost this ability once they switched to Google Maps, and feel completely lost (or write inane articles) if they get bad directions. Which is silly, as Google Maps made ad-hoc route changes much easier. Road seems bad? Turn left. Or right. You are not going to get lost, Google will always keep showing how to go towards direction of the destination.