The way I see it:
crossing=no – crossing here is not legal/possible crossing=unmarked – there are no road markings (or traffic signals) that indicate this is a designated crossing, but based on other factors, it’s a location where pedestrians common cross, e.g. because of lowered kerbs, or because the sidewalk on one side of the road ended crossing=uncontrolled – there are road markings indicating this is a designated pedestrian crossing, but no traffic signals that explicitly tell pedestrians when they have to stop crossing=traffic_signals – there are explicit traffic signals that tell pedestrians when to stop. There are very likely road markings, but even if not, the absence of road markings, in the presence of actual traffic signals, is irrelevant for how this crossing operates. All other crossing=* values that are currently in use are either simply undefined in meaning, or, like the ones listed in the wiki (zebra, pelican, toucan, …) are shorthand for one of the 4 values above + implicit values for additional tags. From: Paul Allen <pla16...@gmail.com> Sent: Saturday, 25 May 2019 05:53 To: Tag discussion, strategy and related tools <tagging@openstreetmap.org> Subject: Re: [Tagging] Non-orthogonal crossing=* tag proposals: crossing=marked/unmarked vs crossing:markings=yes/no On Fri, 24 May 2019 at 20:06, <osm.tagg...@thorsten.engler.id.au <mailto:osm.tagg...@thorsten.engler.id.au> > wrote: As you said, what others suggested, and what would be a welcome addition, is to leave the existing tag untouched (it seems to work fine for most people except you), and tag the special exception where a crossing=traffic_signals doesn’t have road markings with crossing:markings=no I think this is the nub of the issue: what is meant by crossing markings. I think Nick's interpretation is different from that of some on this list. However, your paragraph seems to conform to Nick's interpretation. What do you mean by a crossing with traffic signals AND with road markings? Hint: crossing=unmarked is defined as being a crossing without road markings or traffic lights. Have you ever seen a crossing with lights AND zebra stripes? Which of the two takes precedence? Motorists have right of way if their signal is green; pedestrians have absolute right of way just by stepping on the crossing irrespective of the lights. Does not compute. However, if you include the zig-zag lines before and after the crossing that do NOT define the interaction of pedestrian and motorist but impose conditions on the motorist alone (cannot park, cannot wait, cannot load or unload, etc) as being crossing_markings=yes then you have the dangerous situation that the map leads people to think that a light-controlled crossing (pedestrians and motorists are controlled by the lights) is a marked crossing (like a zebra) where pedestrians have priority. See the problem? But I suspect this is Nick;s interpretation of what a marked crossing is - there are some marks on the road (I can't make sense of his proposals without that interpretation). I don't consider the zig-zag markings before or after the crossing to be relevant to tagging the crossing. Any more than I consider a white line down the centre of the road to mean that it's a marked crossing. Those markings do not define pedestrian/motorist interaction. I agree with Nick (that will surprise him) that these things matter. Somebody with macular degeneration may have lost all of their central vision. It may be far easier to spot a zebra stripe than to see the lights on crossing signals because of relative sizes. In fact, you don't even have to see the stripes, just know that they are there, because pedestrians have priority. That's why it's a bad idea to tag in a way that could lead somebody to conclude that a crossing with signals is a marked crossing. Instead of hunting for the button and listening for the signal, they'll just step into the road knowing (incorrectly) that traffic will stop for them. Could we make the tagging more explicit? For sure. Could we improve the documentation? Yep. Should we say that light-controlled crossings are marked? Nope. traffic_signals and marking are NOT orthogonal, they are mutually exclusive alternatives. Well, in the UK they are - it's possible there's some country where you can have zebra-light-controlled crossings. -- Paul
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