|Indicates a route number that is not signposted with a reassurance marker.|
|Used on these elements|
|Status: de facto|
|Tools for this tag|
|This key page is a stub. You can help OpenStreetMap by expanding it.
Similar pages for structural reference: Key:religion, Key:waterway.
This tag has not gone through a formal proposal/voting process. However, it is in common usage, especially in the United States, where "unsigned" highway routes are typically used by road maintenance crews but not the general public. There may in fact be signs posted with the route number, but they aren't visible or frequent enough to allow for effective navigation by motorists.
The value of this tag follows the same format as ref=*. For example, a way might have unsigned_ref=SR 927B, whereas a relation would have unsigned_ref=927B. This tag should appear on the relation if the entire route has a single reference route number, and on the ways comprising the route in cases of multiple reference route numbers.