[Tagging] Feature Proposal - crossing=marked

[Nick Bolten]

>> - A crossing might be marked on the ground

> Are there traffic signals which control BOTH traffic and pedestrians?  If
so,
> crossing=traffic_signals.   If there are JUST road markings, no
crossing=traffic_signals.

I interpret this to mean: the necessary condition for using
crossing=traffic_signals is that there are signals controlling both traffic
and pedestrians. If only one or the other, it is not a
crossing=traffic_signals.

>> - A crossing might have lighted signals for pedestrians to cross

> Define what you mean by lighted signals.  If you mean a Belisha Beacon or
something else that WARNS motorists that pedestrians cross here but does
NOT control traffic and pedestrians then it's not
crossing=traffic_signals.  A warning light is not a traffic signal.

In this case, I was thinking of a specific "walk/do not walk" lighted
signal.

>> - A crossing might be protected by a traffic light that tells traffic to
stop. That light might be at the crossing or at a street intersection.

> That's crossing=traffic_signals IF it also controls pedestrians.
Walk/Don't Walk ot Red/Green figures or whatever.  Otherwise it's just
traffic lights.  Even if people can cross there, it's still just traffic
lights because the crossing (by people) Isn't controlled, just the traffic
is.  Traffic has to stop when the lights tell them, the pedestrians take
their chances and are uncontrolled.

I take this to mean that the signals do not need to be colocated in order
to tag crossing=traffic_signals, such as in this scenario:
https://www.colchestervt.gov/ImageRepository/Document?documentID=185.

- There are markings on the ground
- There are pedestrian-facing signals
- There are traffic signals at the intersection controlling traffic

If we tag that as crossing=traffic_signals, have we correctly and
consistently communicated all of that information?

As an aside regarding the term "controlled", the OSM wiki doesn't actually
say any of this about whether it's traffic or pedestrians or both being
controlled. What it actually states is that crossing=uncontrolled is
equivalent to a marked crossing or "crosswalk". A marked crossing can have
or lack all forms of traffic signals that we've discussed.

>>> In any sane world, lights to control pedestrians also function as
lights to control traffic.

>> Then we live in an insane world! I'm not aware of any lights that
control both pedestrians and traffic - they are oriented in orthogonal
directions.

> *Sigh*  Was all this about pedantry?  The same interlocked mechanism
controls two sets of lights on the same pole, one set controls vehicular
traffic the other set controls pedestrians.  I didn't mean that both
pedestrians and motorists stare at exactly the same set of lights.

That's not pedantry, it's the precision that we need to describe crossings.
Are we mapping based on lights or a connected signal apparatus? That's an
actually important question. We should be able to say that clearly to new
mappers and embed it into mapping tools.

> I don't think we can let occasional errors by novice mappers define tags
for us.  If such errors are widespread then we need to introduce a
replacement scheme, encourage it for new use and manually replace the old
scheme.

Given that I've received a different definition of the term "uncontrolled"
from every response in this and the other proposal thread, I do not suspect
this is an issue that is occasional nor restricted to new mappers.

On Fri, May 10, 2019 at 1:20 PM Paul Allen <pla16021 at gmail.com> wrote:

> On Fri, 10 May 2019 at 21:03, Nick Bolten <nbolten at gmail.com> wrote:
>
>> I still don't know when you think we should use
>> crossing=traffic_signals...
>>
>> - A crossing might be marked on the ground
>>
>
> Are there traffic signals which control BOTH traffic and pedestrians?  If
> so,
> crossing=traffic_signals.   If there are JUST road markings, no
> crossing=traffic_signals.
>
> - A crossing might have lighted signals for pedestrians to cross
>>
>
> Define what you mean by lighted signals.  If you mean a Belisha Beacon or
> something else that
> WARNS motorists that pedestrians cross here but does NOT control traffic
> and pedestrians
> then it's not crossing=traffic_signals.  A warning light is not a traffic
> signal.
>
> - A crossing might be protected by a traffic light that tells traffic to
>> stop. That light might be at the crossing or at a street intersection.
>>
>
> That's crossing=traffic_signals IF it also controls pedestrians.
> Walk/Don't Walk ot Red/Green
> figures or whatever.  Otherwise it's just traffic lights.  Even if people
> can cross there, it's still
> just traffic lights because the crossing (by people) Isn't controlled,
> just the traffic is.  Traffic has
> to stop when the lights tell them, the pedestrians take their chances and
> are uncontrolled.
>
> - A crossing might be protected by warning lights to raise pedestrian
>> visibility
>>
>
> Not crossing=traffic_lights.  Traffic lights control traffic, at a
> minimum.  If they also control
> pedestrians then they're crossing=traffic_lights.  If they just warn
> motorists they're not
> traffic lights of any kind.
>
>>
>> Which part(s) of that does crossing=traffic_signals describe?
>>
>
> See above.  Just my own opinion, of course.
>
>>
>> > In any sane world, lights to control pedestrians also function as
>> lights to control traffic.
>>
>> Then we live in an insane world! I'm not aware of any lights that control
>> both pedestrians and traffic - they are oriented in orthogonal directions.
>>
>
> *Sigh*  Was all this about pedantry?  The same interlocked mechanism
> controls two sets of lights
> on the same pole, one set controls vehicular traffic the other set
> controls pedestrians.  I didn't
> mean that both pedestrians and motorists stare at exactly the same set of
> lights.
>
> Similar to you, I have yet to find an intersection with a pedestrian
>> signal that does not have some form of either warning or explicit traffic
>> control (but it could be either one), but I wouldn't rule it out based on
>> my experience alone. However, the existence of a traffic light doesn't
>> imply any other infrastructure: the crossing might lack pedestrian signals,
>> its own dedicated light near the crossing, and even any particular visual
>> markings indicating where to cross. Despite this, the
>> crossing=traffic_signals tag has been used to describe all of these things,
>> somehow.
>>
>
> I don't think we can let occasional errors by novice mappers define tags
> for us.  If such errors are
> widespread then we need to introduce a replacement scheme, encourage it
> for new use and
> manually replace the old scheme.
>
> --
> Paul
>
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> Tagging at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/tagging
>
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