[Surface][1] and [smoothness][2] are tags that can be used to describe the state of the roads. For your situation surface=sand plus smoothness=very_horrible could make sense. Caveat: Both tags are not for bicycle use only. The tags should best suit all traffic participants (pedestrians, bicycle, motor vehicles) so don't try to be "too negative". [1]: https://wiki.openstreetmap.org/wiki/Talk:Key:surface https://wiki.openstreetmap.org/wiki/Key:surface [2]: https://wiki.openstreetmap.org/wiki/Key:smoothness

[Surface][1] and [smoothness][2] are tags that can be used to describe the state of the roads. For your situation surface=sand plus smoothness=very_horrible could make sense. Caveat: Both tags are not for bicycle use only. The tags should best suit all traffic participants (pedestrians, bicycle, motor vehicles) so don't try to be "too negative". [1]: https://wiki.openstreetmap.org/wiki/Talk:Key:surface [2]: https://wiki.openstreetmap.org/wiki/Key:smoothness