[Tagging] Non-orthogonal crossing=* tag proposals: crossing=marked/unmarked vs crossing:markings=yes/no

Fri May 24 21:35:53 UTC 2019

> 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.

I think the other definitions match up with the wiki (though they are more
specific here than there).

What does it mean for a crossing to operate and why would ground markings
be irrelevant? The answers to these questions would be definitions of how
to use these tags, if we came to consensus.

For example, my interpretation is that in this case, "operate" is that
contentious idea of "control" of traffic and pedestrians. This is
reinforced by the example of "tells pedestrians when to stop". But maybe
you're thinking of something different. If that is the case, we're back to
square 1: some tags are about ground conditions (unmarked/uncontrolled),
others are about "control" and lights (traffic_signals).

I can't interpret this schema, as a data consumer attempting to route
pedestrians. Too much is left unknown. As a mapper and organizer of mapping
parties, I still have an almost impossible task in front of me explaining
these tags and what to prioritize (ground condition vs. undocumented
"control").

On Fri, May 24, 2019 at 1:09 PM <osm.tagging at thorsten.engler.id.au> wrote:

> 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 <pla16021 at gmail.com>
> *Sent:* Saturday, 25 May 2019 05:53
> *To:* Tag discussion, strategy and related tools <
> tagging at 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.tagging at 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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