add hazard=* tag for highways

[aaei924]

Description, Motivation & Context

By this field, iD editor allows people to map hazard=* key on highway features easily. hazard=* is for boundary and highway, but currently iD tagging schema supports hazard key only for boundary. This PR adds hazard key support also for highways. This single key has been divided into hazard_boundary.json and hazard_highway.json files, because the key has different values depending on features.

This tag has been approved by proposal procedure.

Related issues

Links and data

Relevant OSM Wiki links:

• key:hazard: You can find Wiki page for each values in this page.

Relevant tag usage stats:

https://taginfo.openstreetmap.org/keys/hazard

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[tordans]

This single key has been divided into hazard_boundary.json and hazard_highway.json files, because the key has different values depending on features.

I don't see anything about hazard_boundary in the changes, though.

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[tordans]

@aaei924 the examples at https://wiki.openstreetmap.org/wiki/Proposal:Hazard#Examples all show a combination of tags … but different tags. Mostly traffic_sign, but also boundary, landuse. This PR does not handle any relation to other tags. Is the established practice to just use the hazard key on highway=* without addition?

Another thing I wonder is, that https://wiki.openstreetmap.org/wiki/Key:hazard#Traffic_hazards does not promote tagging the road way too much. Tagging the traffic sign itself is mentioned instead.

And TBH, I wonder why we would want to promote tagging the road way given that those signs are super hard to tag on a way: The have a start but usually not an "end" sign, so one has to come up with a length without being able to verify it. And once we split the road, the sign is copied which would suggest a new traffic_sign object that is not there. We have that same issue with maxspeed of course, but those have a better start and end definition or signage.

So personally I am not convinced we would want those tags to be promoted on ways. Rather having more traffic_sign=* + hazard=* nodes as a vertex or next to the road.

[tordans]

On a technical note, there are some highway classes missing like trunk_link. But lets first talk about the general idea.

[1ec5]

At least in the Americas, warning signs of all sorts can come with “Next X Miles” or “Next X km” plaques. To the contrary, I couldn’t imagine tagging hazard=curve on just a vertex along the roadway, since the extent of the curve is plainly visible and the warning is usually tied to an advisory speed (maxspeed:advisory=*).

[matkoniecz]

this should be clearly about signed hazards, as https://wiki.openstreetmap.org/wiki/Key:hazard mentions

not about subjective rating

if actual tagging degenerated into subjective ratings it must not be promoted by iD

[aaei924]

@aaei924 the examples at https://wiki.openstreetmap.org/wiki/Proposal:Hazard#Examples all show a combination of tags … but different tags. Mostly traffic_sign, but also boundary, landuse. This PR does not handle any relation to other tags. Is the established practice to just use the hazard key on highway=* without addition?

Another thing I wonder is, that https://wiki.openstreetmap.org/wiki/Key:hazard#Traffic_hazards does not promote tagging the road way too much. Tagging the traffic sign itself is mentioned instead.

And TBH, I wonder why we would want to promote tagging the road way given that those signs are super hard to tag on a way: The have a start but usually not an "end" sign, so one has to come up with a length without being able to verify it. And once we split the road, the sign is copied which would suggest a new traffic_sign object that is not there. We have that same issue with maxspeed of course, but those have a better start and end definition or signage.

This tag on highway is seemed to have been intended to use with traffic_sign=* tags.

Many hazard signs even don't have any explicit end sign, but in some cases, for example, most of hazard=school_zone signs in Korea have their end sign on the road. We had better add this tag on ways only in cases we can find out where they start and end. If we don't know where the end point is, just placing a node and applying hazard tag may be encouraged.

[1ec5]

Even if a warning sign doesn’t come with an explicit distance, it often still has a natural start and end because the same sign is posted as you approach from either direction. (This only applies to two-way roads, of course.) I think users would be able to figure that out themselves, but if not, the help text from the data item could suggest the right method.

[matkoniecz]

Descriptions at https://wiki.openstreetmap.org/wiki/Tag:hazard=dangerous_junction and other tag pages should also be fixed

right now it looks like permitting 100% subjective tagging

while https://wiki.openstreetmap.org/wiki/Key:hazard is clear that it is about signed hazards on roadways

[aaei924]

Descriptions at https://wiki.openstreetmap.org/wiki/Tag:hazard=dangerous_junction and other tag pages should also be fixed

right now it looks like permitting 100% subjective tagging

while https://wiki.openstreetmap.org/wiki/Key:hazard is clear that it is about signed hazards on roadways

@matkoniecz I've just edited that wiki page. I clarified that the tag is only used when there's a traffic sign.

[matkoniecz]

note "and other tag pages should also be fixed"

I checked random one - https://wiki.openstreetmap.org/wiki/Tag%3Ahazard%3Dchildren and it is also missing info that it is valid only for signed hazards

other value pages also should be fixed

[matkoniecz]

Is anyone planning to fix documentation?

[aaei924]

Is anyone planning to fix documentation?

I changed all documents of approved values at traffic hazards. It's good to proceed.