The tag oneway can be ambiguous on highway=footway and =path: Did the mapper mean oneway for pedestrians or did they mean vehicles (usually bicycles) who may be allowed to use the way?
There’s been a lot of discussion on this and now I am thinking of writing a proposal (following the proposal process) to discourage the use of oneway on footway and path, and promote the use of existing unambiguous alternatives. For the full rationale and an informal poll on whether such a proposal would be a good idea, see the existing thread here.
To say that pedestrians can only use the way in one direction, there are currently two alternatives. For the proposal, we should choose one of them, this will be the one that we can recommend to mappers, and also to editor developers to use in presets.
What I dislike about oneway:foot is that it appears to also use the syntax of conditional restrictions on the surface, but subtly breaks the inherent logic of that tagging system:
With conditional restrictions, appending a suffix (such as :foot) to a key generally restricts its meaning to a certain group of users or a certain direction. But because pedestrians aren’t included in oneway=* according to the current definition, a hypothetical oneway:foot key would have to expand the meaning of the base key.
Hypothetically, it would be possible to bring oneway:foot in line with conditional restrictions without this special exception. But that would require dropping the built-in assumption that oneway doesn’t apply to pedestrians and always make it explicit who the oneway restriction applies to. That is, use oneway:foot=yes for the use case discussed in this thread and oneway:vehicle=yes for the common traffic sign.
How about cycleway? There are countries where a combined sidewalk + cycle track is tagged as cycleway, right? So we need to include it and possibly even bridleways.
The “elephant in the room” here is that I suspect that a number of highway=footway;oneway=*;some_other_mode!=no might actually not the best way of tagging a particular feature at all, and only a proper survey will fix that.
The obligatory missing option (!) is just to leave the oneway if no other modes are involved since it’s the least confusing to all concerned.
You are right, I got confused that despite the title only path and footway are mentioned in the description.
I think it would have been better to only link to the poll in the other topic as now the discussion is split into two topics and I only can quote myself:
Thanks! I can see where you are coming from. If we assume that the oneway tag only ever applies to vehicles and that it is nothing more than a translation into OSM tagging of a traffic sign that, as traffic signs do, only applies to vehicles, then of course a one-way hiking path in the mountains with the oneway tag has simply been tagged wrong and needs to be corrected.
This is precisely the opposite of the argument that @SomeoneElse is making: that oneway on a footway for a one-way hiking path is perfectly fine (unless there is also a bicycle=yes or similar, then it becomes ambiguous).
We discussed this quite a lot in other thread and a lot of examples came up and I came to the conclusion that there is no clear majority for either view, so I am proposing a compromise: Avoid using oneway on footway and path altogether, and use a more specific tag wherever possible. But which one is the more specific tag that we should recommend? That’s what this poll is about.
That’s exactly what I am trying to address. Ideally when someone tags highway=footway bicycle=yes oneway=yes, or when someone looks at a way that has been tagged like this, I’d like to see a validator warning pop up that says “Are you sure? The oneway tag is ambiguous. Use oneway:bicycle and [either oneway:foot or foot:backward] to specify one way restrictions for each mode of transport separately."
But for that we should have some consensus in the community first (hence the proposal idea). Let me know what you think! (For comments on whether such a proposal is a good idea at all, the other thread is probably best.)
oneway=yes has the default meaning “vehicle:backward=no, foot:backward=yes”. In effect it’s a more user-friendly short cut to represent the latter. (Incidentally I’m still not sure if horse defaults to the same as vehicles).
oneway:foot=yes is similarly a short cut for “foot:backward=no”, for use either when the default oneway=yes meaning does not apply, or when it might be unclear. The equivalents for moped, bicycle, horse etc. have a fully consistent interpretation.
This avoids having to explain to mappers why foot oneway has a completely different format to all other forms of transport: it is not contradicting anything, it is just expressing a difference to the default meaning. Just as adding bicycle=yes to a footway doesn’t contradict the footway tag, it just specifies a non default access.
depending on where oneway tag is - in some cases it actually gives info that something is oneway for pedestrians (no matter how much it is disliked by some definition purists)
yes but in this cases it is not foot:backward=yes - there it is foot:backward=no!
So the statement that oneway=yes inplies foot:backward=yes ist totally wrong!
oneway never adds a “access=” yes. it only sets one direction “access” to no in the one or the other direction.
On roads:
oneway=yes overwrites all types of “vehicle”:backward with no
oneway=-1 overwrites all types of “vehicle”:forward with no
oneway=no does nothing.
It shows that implicit “access”=yes (beyond highway tags) is complicated because you have to consider in which order the tags are interpreted, and this order is not documented well.
1 highway default access
2 motorroad=yes default
3. access tags from general to special
4. oneway=yes/-1 tags set one direction to no
It is dangerous to say oneway=yes is only a shortcut for vehicle:backward=no.
E.g what does this mean?
vehicle:backward=no + bicycle=yes
Is this a oneway for bicycle or not? Does bicycle overwrite vehicle:backward?
depending on where oneway tag is - in some cases it actually gives info that something is oneway for pedestrians (no matter how much it is disliked by some definition purists)
I would say who put it wanted to express that it is oneway for pedestrians, but as these are only a few fragile exceptions compared to the rest of the usage, “giving info” does not describe the situation.
The more specific tags overrule the less specific ones. So it is a oneway for all vehicles, but not for bikes.
Is this a oneway for bicycle or not?
not
Does bicycle overwrite vehicle:backward?
yes
But I agree that so far probably oneway=yes+bicycle=yes was meant to be a oneway for bicycles as well, so interpreting oneway=yes as vehicle:backward=no and applying the logic as above wouldn’t be so straightforward.
