| +/- access=designated
A way marked for a particular use.
If you are mapping Public Rights of way in the UK (specifically England and Wales) see UK public rights of way.
This tag indicates that a route has been specially designated (typically by a government) for use by a particular mode (or modes) of transport. The specific meaning varies according to jurisdiction. It may imply extra usage rights for the given mode of transport (i.e. normally a vehicle is banned, but in this case it is allowed), or may be just a suggested route (e.g. bicycles can in most jurisdictions ride on any street, but some particular streets are recommended and signed as such.) . To indicate an exclusive access see access=official, or just use access=no in addition to a mode-specific key (foot=designated, bicycle=designated, etc.)
Just as in other cases, if the designating sign implies restrictions on other modes of transport those restrictions should be tagged with their respective tags.
Some places have designated snowmobile routes everywhere
The trail marked with the sign shown in the example picture (top right):
A UK bridleway:
A UK cycleway:
A UK footway:
A truck route in the USA: