From OpenStreetMap Wiki
|highway = abandoned|
|DEPREACTED! Highway which was abandoned because of change in natural change or change of route.|
|Used on these elements|
|Tools for this tag|
|Tag abandoned=yes is deprecated, please do not use it. Use lifecycle prefix abandoned:=* instead.|
A former (very) busy road, which is no longer used or can not be repaired (it is in very bad condition).