|Indicates a route number that has assigned ref that is not prominently signposted with a reassurance marker.|
|Used on these elements|
|Status: de facto|
|Tools for this tag|
It may be not signposted anywhere at all, what is a typical situation. But in some rare cases there are tiny, unusable by drivers, signs.
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.
This tag has not gone through a formal proposal/voting process. However, it is in common usage.
It is useful in cases where "unsigned" highway routes are typically used by road maintenance crews but not the general public. For example in United States this tag is popular - 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. Also in other countries, for example in Poland many minor roads have officially assigned codes but these codes are not used by general public and are not posted anywhere at all or with barely visible signs.