I stumbled over some maxheight=none tags on motorways, that did not even pass under a bridge. I found that this is the most frequent value of maxheight (2889 of 41474).
On an open highway that tag makes no sense for me at all. No height limit is implicit, though somewhere could be a powerline crossing the road which is hard to verify. Under a bridge, it makes no sense for the opposite reason, the bridge does have a physical height restriction, even if it is not signposted, and/or the default for the country. Thus maxheight=none under a bridge is wrong (as opposed to maxspeed=none on a German motorway, where the speed is indeed theoretically unlimited). For bridges without sign, there is no recommendation in the English wiki, however the German wiki proposes maxheight=unsigned (290 uses), also used is maxheight=default (303) and =unspecified (2). I would recommend to add maxheight=unsigned to the English and other wiki pages, and list maxheight=none as incorrect tagging. Tom _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging