On Wed, 9 Dec 2020 at 18:13, Brian M. Sperlongano <zelonew...@gmail.com> wrote:
> > >> Here are the ones that I think are worth considering: >> >> - Opening or swing bridge ahead >> >> This is already covered by the approved tag bridge:movable and its > various sub-keys that describe different types of movable bridges. > For the swing bridge, it's covered. But the text says "Opening or swing bridge." I have no idea what an opening in a route might be if it's not a movable bridge but maybe somebody else on the list does. - Overhead electric cable Overhead powerline cables are already mapped, it seems that would be > sufficient to know that there is an overhead cable. > Only if the height of the cable is specified, and it rarely is. In my country there are minimum clearances in most cases, and only extra-tall vehicles need to take special care. But there are cases where the clearance is lower than might normally be expected. My feeling is that if some authority thinks a cable needs a warning sign then it should be considered a hazard. - Hidden dip Maybe. There is a barely used tag hazard=dip. Is this a permanent feature? > I don't know. I don't recall ever seeing that sign. But in my part of the world we have old hump-backed bridges so it's conceivable we have roads with hidden dips, too. One not covered there is the warning that a route is unsuitable for long >> > vehicles. There are a few minor roads near me like that. Drive a long >> vehicle along them and (at best) you have a long reverse or (at worst) >> you get stuck. >> > > Since we have tags to describe the width of roads, and the ways making > them up have a geometry associated with them, it seems that this is > something that routers could simply calculate based on existing tagging. > Routers could calculate it, but at what computational cost? Maybe it's something they do anyway, so zero cost. Maybe it could be derived from something they already do, so low cost. My guess is that they don't examine road geometry in that much detail, if at all, and it would be expensive. Also, think of a T junction. A sharp, 90-degree turn. In practise, lane widths give some leeway for the turn. In practise, junction corners may be rounded to allow long vehicles to turn. Routers which tried to evaluate road geometry for long vehicles could end up incorrectly discarding T junctions. Digging around, I found https://www.legislation.gov.uk/uksi/2002/3113/schedules/made which lists several "unsuitables": heavy goods vehicles, long vehicles, wide vehicles, buses, caravans, trailers, articulated vehicles. Some of those might be better handled by the appropriate access restriction, if we had access restrictions for them and if this were a legal prohibition (it isn't). > > >> Also, in the UK, the sign for unexploded ordnance is the same as you >> have for minefields. That symbol first appeared in UK Defence Standard >> 05-34, Marking of Service Matériel, and was called (bizarrely) "Unexploded >> explosive ordnance" (if it has exploded it would no longer be explosive, >> and if it's explosive then it must be unexploded). In old money it >> would have been called "unexploded bomb." >> > > Thanks! This is not a sign I normally see on my daily commute :) > I did some more digging. It's not a sign associated with minefields unless those minefields also have unexploded ordnance that isn't mines. There is no standard sign for minefields, but there is a semi-standard. See https://studioissa.com/warning-signs-how-landmines-can-teach-us-about-project-design-and-communication/ and https://www.mineactionstandards.org/fileadmin/MAS/documents/archives/IMAS-08-40-Ed2-Am1.pdf -- Paul
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