Ask for kerb type on public transport stops

FloEdelmann commented 9 months ago

General

Affected tag(s) to be modified/added: kerb Question asked: What is the height of the curb here?

Checklist

Checklist for quest suggestions (see guidelines):

[x] 🚧 To be added tag is established and has a useful purpose → especially for wheelchair users
[x] 🤔 Any answer the user can give must have an equivalent tagging (Quest should not reappear to other users when solved by one) → see existing AddKerbHeight quest
[x] 🐿️ Easily answerable by any pedestrian from the outside but a survey is necessary → see existing AddKerbHeight quest
[x] 💤 Not an overwhelming percentage of quests have the same answer (No spam)
[x] 🕓 Applies to a reasonable number of map data (Worth the effort) → see https://overpass-turbo.eu/s/1And

Ideas for implementation

Element selection: nodes, ways with public_transport = platform and kerb = yes Metadata needed: None Proposed UI: see existing AddKerbHeight quest

Note: OpenStop already asks the same question, see https://github.com/OPENER-next/OpenStop/blob/v0.5.0/assets/question_catalog/definition.json#L804-L851

peternewman commented 9 months ago

What's the expected answer at a railway or subway station? Or is the theory they won't be tagged with kerb/it's an error?

Also how does this interact with buses that kneel down or deliberately high kerbs to reduce the step up to the bus?

FloEdelmann commented 9 months ago

is the theory they won't be tagged with kerb/it's an error?

Exactly.

how does this interact with buses that kneel down?

Buses that kneel down still can't reach the street level, so lowered or flush kerbs would still be a bigger obstacle than raised.

deliberately high kerbs to reduce the step up to the bus

It seems like there is no tag for that, so it would still be raised.

westnordost commented 9 months ago

Err, you mean a kerb to enter the platform? Or a kerb towards the road? Is this defined somewhere? How often is this tag used in conjunction with public transport platforms?

FloEdelmann commented 9 months ago

It's the kerb towards the road. See also https://wiki.openstreetmap.org/wiki/Key%3Akerb#To_add_information_to_another_map_feature:

kerb=* is also used on a highway=crossing, highway=bus_stop or similar to provide information about the kerb at this point. This usage indicates that there is a kerb somewhere near this node that someone visiting the node might want to know about, but it does not imply that everyone visiting this point has to cross the kerb, so barrier=kerb should not be used on such nodes. (In fact, a raised kerb at a bus stop may exist to make it easier for people to get on the bus.)

The combination public_transport = platform and kerb is used 27k times: https://taginfo.openstreetmap.org/tags/public_transport=platform#combinations See also the Overpass query: https://overpass-turbo.eu/s/1And

westnordost commented 9 months ago

I see. But then, I do not really see the use of this tag on public transport platforms, as at pretty much all bus stops there are raised kerbs toward the roadway (💤). What may be useful to know is whether the platform has even higher raised kerbs which may not make it necessary for buses to have this kneel-down functionality or ramp-functionality (?). But this is not possible with kerb=* tagging.

Even so, whether a bus route is usable for wheelchair users depends to a somewhat higher degree on the buses, not on the platform. If the buses do neither have the kneel-down nor the deployable ramp, I'd say the kerb doesn't matter at all and if the bus has these features, it matters only a little bit. In any case, we do not map these properties of buses.

FloEdelmann commented 9 months ago

at pretty much all bus stops there are raised kerbs toward the roadway

There are quite many bus stops with kerb and kerb != yes and kerb != raised: https://overpass-turbo.eu/s/1Aq1

If the buses do neither have the kneel-down nor the deployable ramp, I'd say the kerb doesn't matter at all

A lowered or flush kerb would still be a bigger obstacle than a raised kerb. This is helpful information for wheelchair users (maybe with an assistant person), for parents with baby strollers, elderly people (with or without rollators), …

westnordost commented 9 months ago

And how much is that in percent?

Am 14. September 2023 09:56:53 MESZ schrieb Flo Edelmann @.***>:

There are quite many bus stops with kerb and kerb != yes and kerb != raised: https://overpass-turbo.eu/s/1Aq1

If the buses do neither have the kneel-down nor the deployable ramp, I'd say the kerb doesn't matter at all

A lowered or flush kerb would still be a bigger obstacle than a raised kerb. This is helpful information for wheelchair users (maybe with an assistant person), for parents with baby strollers, elderly people (with or without rollators), …

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FloEdelmann commented 9 months ago

According to a quick semi-random search on Overpass Turbo, ca. 90% of all non-yes kerb values on public transport stops are raised. So ca. 10% are lowered or flush.

westnordost commented 9 months ago

That's unexpected, I'd have guessed many more to be raised. Could it be that the data is skewed towards that the more unusual case is tagged and the standard case is not? I guess we can't know that. Since less than 1% of platforms are tagged with this, it's impossible to say how representative this data is.

I am still somewhat inclined to mark this as will-not-fix because of the second paragraph in my penultimate post in this thread.

To be honest, I do not want to appear that I pull new reasons to not implement this out of my ass, but what I am most concerned about (after asking users 💤 pointless questions) would be how it would be received by the community if StreetComplete started tagging it on all bus stops.

Would it help to discuss it prior in the forum? Probably not.

What would help would be to document this property properly, e.g. also with some example photos where indeed the kerb is not simply raised.

What would also help would be to address the concern how or if it makes sense to distinguish normal kerbs from those specifically raised ones seen at some modernized accessible bus stop platforms. Because... that's the point, isn't it? We want data on which bus stops are accessible (=barrierefrei). But so far, it seems it is not possible to tag this with the kerb=* tagging scheme

Both the left part (=accessible raised kerb) and the right part (=normal raised kerb) are tagged with kerb=raised, no distinction made whatsoever in OSM. (Picture is a link that links to some German article about barrierefreie Bushaltestellen)

FloEdelmann commented 9 months ago

@Robbendebiene, @7h30n3, @yulieth9109, @wielandb: As maintainers or main contributors in https://github.com/OPENER-next/OpenStop, is it okay to ping you? Please let me know if it isn't!

Do you know about any other documentation of this tag on bus/tram stops? Or about a tagging proposal to map bus/tram stops with even higher kerbs?

wielandb commented 9 months ago

Hey @FloEdelmann! Yes, feel free to ping us if there are questions we may be able to help because of our efforts in accessibility mapping. 🙂

OpenStop asks two questions about kerbs on platforms. First, it asks how the kerb looks, where it uses the same answers as e.g. StreetComplete does on kerbs on ways. After that, if kerb=raised is selected, it will ask if there is a special "approach aid" on the kerb or if it's just a raised kerb, using kerb:approach_aid.

We initiated a now completed proposal to approve kerb:approach_aid as the tag to measure if such an approach aid is present. Proposal Page, Wiki Page We noticed through your question that I forgot to add the tag to the wiki pages for public_transport=platform 😅 - fixed that now!

Values for kerb:approach_aid are approx. 60% no, 40% yes which should have a fairly small "speciality bias", because much like StreetComplete, OpenStop will tag yes and no.

Regarding "really high kerbs", we noticed through our consultation with different partners that indeed the presence of an approach_aid alone does not satisfy the knowledge if a stop is accessible. We add height= to the platform to try to provide this information. Image of what we ask users to measure. Although, this last question is only available in "expert mode", because it requires to go into the busway which may be dangerous.

westnordost commented 9 months ago

kerb:approach_aid

Hmm, good to know that a tag exists to differentiate normal raised kerbs from specially raised ones for buses. So it sounds like this is doable.

However, rather than two questions, I think it would be better to combine the "approach aid" kerb into the answers, i.e. not have two quests for that. Question is, how to name this option. "Approach aid" is a term no normal person knows. Maybe something like "Raised, for buses"

FloEdelmann commented 9 months ago

@westnordost I think you misunderstood the kerb:approach_aid tag: A curb with an approach aid is not higher than a normal raised curb. The approach aid is a rounded corner between the curb and the street surface, to allow buses to go closer to the curb. So it's minimizing the horizontal distance, not the vertical distance.

westnordost commented 9 months ago

Oh well, but how does it matter? The term I suggested was "Raised, for buses", which should be fine regardless of the (exact) height. One would just need to select a picture that does not suggest that it is also (considerably) higher than normal kerbs.

mnalis commented 9 months ago

Oh well, but how does it matter?

well, it is confusing (especially if those approach aids are rare or nonexistent in some city or even whole country), and might result in user choosing the wrong answer.

The term I suggested was "Raised, for buses",

Yes, but that is easily confused with "Raised for buses", which implies that it has extra height (has been extra raised) for buses.

I have doubts about being able to easily obtain have clear enough photograph which could not be confused; perhaps technical stylized drawing like crossection column on a wiki would be better. But in any case to avoid issues I'd rather put some more telling text like maybe Sloped for buses or Curved bus approach kerb or similar which does not involve mentioning height at all (if it mentions height/raise, it is going to confuse many people IMHO).

osmuser63783 commented 8 months ago

I do not really see the use of this tag on public transport platforms, as at pretty much all bus stops there are raised kerbs toward the roadway (💤).

In the countryside a bus stop might not have a kerb because there isn't a sidewalk.

According to a quick semi-random search on Overpass Turbo, ca. 90% of all non-yes kerb values on public transport stops are raised. So ca. 10% are lowered or flush.

Actually the most common value after raised is no. (See https://taginfo.openstreetmap.org/tags/public_transport=platform#combinations)

The real issue in my view is that public_transport=platform with kerb=yes is even rarer (only 405 examples worldwide). You would first need to have a quest that asks if there is a kerb at all.

westnordost commented 7 months ago

"Special kerb for buses"?

FloEdelmann commented 7 months ago

Hmm, I fear that would also fit curbs without an approach aid but which are higher (specifically for buses) than the raised curbs for normal sidewalks. I think "Sloped for buses" is the clearest wording so far.

westnordost commented 7 months ago

The problem with "sloped for buses" is, that "sloped kerbs" also exist and here the "sloped" refers to the kerb itself, not what is basically in front of the kerb. So you say that it fits curbs without an approach aid but which are higher specifically for buses, but why is it higher? I would say it is higher to aid people on wheelchairs entry, maybe not as effective as this kind of specially sloped kerb, but it is still an aid to enter and exit the bus, isn't it?

FloEdelmann commented 7 months ago

"sloped kerbs" also exist and here the "sloped" refers to the kerb itself, not what is basically in front of the kerb

Hmm, indeed.

I would say it is higher to aid people on wheelchairs entry, maybe not as effective as this kind of specially sloped kerb, but it is still an aid to enter and exit the bus, isn't it?

It is a "boarding aid", but not an approach aid. Note also how the term is defined in the wiki page for the kerb:approach_aid key:

An approach aid is a specially formed kerb that helps buses to approach a platform. When the bus is approaching the platform, the curved kerb automatically guides the tires of the bus along the platform.

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