The following is a sign along a motorway denoting the turn for a park, and the relevant amenities at the park. I would think that it would be something like tourism=information + information=guidepost, but I’m not sure exactly.
Another sign of similar purpose would be something like the following denoting the turn for a park:
These look like traffic signs, which you can map as traffic_sign=* nodes. If these examples are in British Columbia, you might find a relevant sign number among the Information and Service & Attraction sign categories; otherwise, you could use a more generic tag such as traffic_sign=destination along with destination:symbol=*.
