|A difficulty rating scheme for bridleways|
|Used on these elements|
|Tools for this tag|
Some path segments, in particular bridges, can be hard to ride or even dangerous or impossible. horse_scale=* is used to classify the relevant properties of an off-road track. It expresses the difficulty of a road, like sac_scale=* does for hikers.
horse_scale=* is tagged on rideable tracks and paths that have inherent difficulties or dangers. Potential problem areas such as bridges, tunnels and fords can also be clarified.
horse_scale=common is the default and indicates that the way or path is checked regarding horse issues.
When a way on the map looks broad, flat and OK to ride, but has hidden dangers or difficulties, it is recommended to add a note=* with a brief explanation of the problem. Although it isn't displayed on any map, it informs fellow mappers and helps to prevent deletion by someone who isn't familiar enough with the way.
When a short section of a path has a problem that cannot be avoided, e.g. a problematic bridge, you should tag the whole way with the scale of the difficult point, up to the nearest junctions, as you have to pass through the difficult point if you take this way.
Sometimes one can find ways that have no official horse access restriction but that are tagged with horse=no because someone wanted to mark the road as unsuitable for riders. This access restriction is a tagging error, because horse=no is for ways where riding is legally prohibited. The access restriction should then be replaced with a horse_scale=*. Conversely, roads where you are legally disallowed to ride should not have a horse_scale=* tag.
|horse_scale=common||No problems||Way is good for horse riders of all levels.|
|horse_scale=demanding||Be careful||Uneven way, some problem points. Care should be taken, and your horse should be calm and reliable.|
|horse_scale=difficult||Difficult trail||Narrow way, difficult for large horses. May include obstacles that have to be jumped over. Still rideable though.|
|horse_scale=critical||Only for the experienced||Particularly narrow and uneven way. Difficult, even for smaller horses. Only for experienced riders and horses. Often no place to manoeuvre in front of an obstacle. Usually has to be ridden with long reins, dismounting may be necessary from time to time. Large obstacles to climb. Bridges may not be able to bear your weight: inspect them beforehand. Use at your own risk.|
|horse_scale=dangerous||Dangerous||Difficult, dangerous and contorted way. Only for very experienced riders and horses under good weather conditions and with non-slip horseshoes, dismounting is often necessary. Horse needs enough space to move [please improve this translation. original (DE): Aktionspielraum]. Average horses cannot deal with the obstacles. Often not enough space to turn around, going back is hard or impossible.|
|horse_scale=impossible||Impassible. Danger to life||Way or bridge is impassible for horses. Insurmountable obstacles such as ladders or climbing sections with safety rope. Not wide or high enough for horses. Rotten or thin bridges that may collapse when a horse passes over it.|
You can find the discussion about these tags in the OSM Forum (in German).