On Aug 11, 2014, at 9:39 AM, Richard Z. wrote: > On Mon, Aug 11, 2014 at 12:40:57AM +0200, Colin Smale wrote: > Hi, > >> http://farm2.static.flickr.com/1263/1186115057_7f88a4aaed_o.jpg > > looks like a landmark or tourist attraction to me and a narrow single > lane bridge. The speed limiting factor on this particular bridge might > be that you don't see far enough? > > But using bridge=humpback to imply a hazard may not be such a good > idea, will American tourists be familiar with the dangers of humpback > bridges? > > Instead we could describe the hazards as visibility, bump, dip, and > narrow single lane with higher chances of universal usability. > > We could also use reasonable_max_speed (per vehicle category) or > do both. > > Hence I am now inclined to tag humpback bridges as > bridge=yes + bridge:structure=humpback > > Richard
The image reminds me of a bridge, no longer open for traffic, on the old National Pike in Western Maryland. I can see where one might want to reduce speed on one of those to avoid bottoming out or becoming airborne. I think rather that bridge:structure=humpback I'd prefer bridge:geometry=humpback. At least something that conveys shape meaning. For me structure implies the design element that gives a building, bridge, dam, etc. its strength. In the case of the photo that would be masonry arch for structure. For what it is worth, in the Southwest of the United States there were, and still remain, the reverse geometry in the form of "dips" where a road crosses a normally dry water course. Since the is usually only water in them an hour or so a year it used to be deemed too expensive to put in proper bridges or culverts. They are generally signed with a "dip" warning sign and you can certainly get airborne or bottom out on those too. I wonder if a tagging that specifies a rapid change in grade on a road way might be better than a bridge specific tag. Then one set of tags could be used for both sets of situations. Might make it easier on the data consumers. Maybe highway:elevation_change=yes. -Tod _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
