Local laws in my area (Seattle, WA, US) officially create crossings at nearly all intersections even when there are no markings, signals, or signage, so yes, in my region I would tag those as:
highway=footway
footway=crossing
crossing:markings=no
crossing:signals=no
I could understand arguments for crossing=informal or informal=yes depending on the local laws and understanding of what defines a crossing; regardless, mapping of the “not-crossings” is unrelated.
Municipality use all kind of constructions to cross, over a road or a junction.
They use a driveway_link (3) to the drive way (4) owned by the landowner. This (3) has multiple use is owned by the municipality, it is intend to be a part of the crossing (2) but you can only set *=crossingon a footway, path, cycleway, there for there a visualisation of tags.
Routing is a schematic thing, on the other hand we map topographically, we put the line in the middle of the road. Trying not to draw crossed, skewed lines. Therefore, we chose to set one section of the road (6) to foot=yes ( green (yes) pedestrian), the remaining residential will get foot=use_sidepath.
At (5 ) that is not a crossing, one could use another name for it. The residential (yellow) is at a junction with crossing located on a traffic_calming=table with the connection for foot barrier=kerb kerb=flush.
An identical law applies throughout California, but over here we haven’t been creating these theoretical crossings as a rule:
It’s one thing to map a crossing aggressively in a quiet residential neighborhood but quite another to map one in a business district where there’s usually a good reason for the lack of any crossing accommodations. I’m not against mapping something so that one of these theoretical crossings doesn’t get confused with a crossing=no situation (due to signs or sheer impassability), but it should be something other than a highway=crossing or footway=crossing that needs to get canceled out by a variety of secondary tags.
I think part of the problem for quiet residential neighbourhoods in Ireland is that there isn’t really any special legal status for pedestrians at intersections, compared to crossing the road in the middle of a block. Sometimes there might be physical indications of an intention that pedestrians cross at certain places, such a dipped kerb. In street level imagery I can see that there are dipped kerbs for pedestrians proceeding on the east side of the street - as reflected in the mapped crossing. But there is no specific provision for pedestrians wanting to cross from west to east. In practice it is easy enough to cross by choosing one of the driveways and taking advantage of its dipped kerb. But I can certainly understand why a mapper wouldn’t map a crossing there.
On “private” driveways, would you split the way into “private” and “non private” parts of the driveway? Or would the part between the footway and centre line have some completely different tag to indicate it is a “link” rather than an actual driveway?
The length of the conflict is only one risk factor. A rigorous analysis of collision risk would need to consider not only the conflicting feature more holistically, using whatever tags you might find on the crossing feature. Given that, I don’t think it’s unreasonable to expect a crossing driveway to have width=* or a proxy like lanes=* in order to satisfy this use case, even if that’s currently about as rare as isolating a footway=crossing at a driveway.
For example, I don’t think we can assume that a long conflict with an uncontrolled parking lot is proportionally riskier than a short conflict with a gas station entrance:
A pedestrian railway crossing could be risky or not depending on the track classification:
I don’t quite understand this line - it sounds like there is an unmarked crossing at those locations you are choosing not to map. That’s fine - no one is saying you are obligated to map those, but it’s the responsibility of the renderer, router, and traveler to weigh the costs and pick the appropriate crossing depending on their needs.
A traveler in a wheelchair during a busy time of day would want their router to penalize unmarked, unsignalized crossings intersecting high-classification roadways; an able-bodied athlete out for a run during a quiet time of day would not want to be routed pointlessly around the valid crossing and across three well-delineated ones just to cross the road.
I disagree - it’s the other crossings with markings or signals which are elevated above the unmarked or unsignalized crossings; to assume that a crossing has markings and signals by default (and that this needs to be “cancelled out” by additional =no tags) is incorrect.
Definitely agree - something like (intersectingHighwayClassification x crossingLength) does give a better picture, and one valid way to map that crossingLength is with a crossing way along its length. This is the inherent step up of information from node → way → area.
An aside: Thanks, as always, for your detailed and well-considered responses @Minh_Nguyen 
I appreciate your engagement and perspective.
In the example I gave, there’s unquestionably an unmarked crossing across Edwards Avenue (the side street in the following photo). There are curb ramps on either side, and the stop line has enough of a setback to give pedestrians ample room to cross. The question is whether there’s also a pair of unmarked crossings across South First Street before and after this intersection.
Legally speaking, pedestrians can cross all three sides of the intersection, because there’s no sign legally prohibiting pedestrians from crossing South First. However, there’s also nothing that would facilitate the crossing. Unlike Edwards, South First is an arterial road, along which there are many marked and signalized crossings – just not here. There’s no curb ramp on the other side of South First. A pedestrian crossing South First tangentially from the curb ramp at the corner would have to physically step on the double yellow centerline. A series of marked parking stalls doesn’t accommodate the tangent line either (and all the stalls are usually occupied). These factors strongly suggest that crossing here would be tantamount to jaywalking, if not in the eyes of the law then to any reasonable observer.
Context matters. Mapping three crossings at this intersection would be pedantic and counterproductive. We’d have no clear way to distinguish the theoretical crossings from the more obvious crossing across Edwards, based on the factors that I enumerated. It isn’t enough to map kerb=raised nodes on one side of South First, because there are still plenty of bona fide crossings around the city that have a mix of lowered and raised curbs.
As it happens, there’s also a driveway jutting out the other side of this intersection. I never noticed it because it’s fenced off and probably unused. So technically there is an opening in the row of street parking stalls and a convenient driveway apron, which an adept pedestrian could take advantage of by crossing diagonally (if not for the illegally parked car).
In my opinion, mapping a pair of crossings across South First would go well into the realm of hypotheticals and for questionable benefit. I also wouldn’t bother to map a crossing across the driveway, where there would otherwise be a sidewalk anyways, but at least the downside to mapping it as a crossing wouldn’t be as severe.
This isn’t what I’m assuming. Rather, I’m pointing out that three distinct scenarios have come up in this thread so far: marked or signalized crosswalks, unmarked and unsignalized but otherwise discernible crossings, and purely theoretical crossings. Mapping this third category as ordinary crossings dilutes the value of mapping the other categories. Perhaps if the streets were unpaved, as some were across town not so long ago, we’d be able to map some informal crossings based on apparent desire lines, but not as things stand today.
@apm-wa may I ask why this was moved? It makes no sense here (and also disabled my e-mail notifs)
Done on request of the user who posted it.
crossings are dependent from a local law.
Here at Poland to have a marked crossing you need to have a sign on a pole, painted markings can’t be a marked crossing on their own.
If the road boundary kerb goes through a sidewalk without a crossing, then there is a possibility to say it’s actually an unmarked crossing and vehicles take a priority by going into that driveway, but it’s tricky and you cant be 100% certain about it at court.
Also, we are used that a crossing is tagged only for pedestrians or bikes, but it’s actually the vehicle street that crosses a sidewalk… we don’t even have tags for that.
We when a cyclewey crosses footway or a footway crosses cycleway, we have just one tag for that and it doesn’t specify which one is crossing the other.
Among things i have elaborated about it there on point 2.
