I would maybe question that. There is no general tag to tell that a track is used for snowmobile in winter except snowmobile=designated. Am I right?
For skiing, having piste:type=nordic or downhill + an access tag is much easier to understand.
Maybe something like piste:type=snowmobile or an equivalent tag would convey the snowmobile designation better?
access= is legal restriction, not anything esle. =designated does not mean priority.
You can use highway=footway here.
This is not ambiguous. Your other interpretation is not possible. access= is already treated as to be overridden by individual modes. You should use snowmobile=permit, ski=customers, and atv=private respectively.
An official trail might be represented by route= =snowmobile, =piste (and/or piste:type), and =atv. The construct of a road should be on highway= (viz =track) and related.
I do prefer :conditional=* @ (permit) over =permit, but I don’t see this as a “clash” per se as @Hungerburg.
Perhaps some ideas from parking lane tagging could be borrowed for snowmobiles. Something like
snowmobile=designated
snowmobile:condition=permit
(Like parking:condition=no_stopping rather than conditional)
This also seems analogous to tagging a situation like bus=designated + bus:lane=yes|designated + turn:lanes=yes|no, where a roadway is designated for buses but more nuance is needed to explain other vehicles can use a lane of it for turning.
I don’t know much about snowmobiles, but a lot of other vehicles can be tagged with subkeys relating to extremely specific access and condition configurations. Putting aside disagreements about what designated and permit tags are for, maybe snowmobile mapping hasn’t been taken to the level of detail possible yet since it seems like there are more options to tag complex situations involving other vehicles
My non-serious idea would be to tag it as a tollway for snowmobiles
snowmobile=designated
snowmobile:condition=permit
note that in current tagging it would miss info that access requires ordinarily granted permit
I would rather use new tag for “and it is a designated snowmobile route” (and often it can be marked with route relations!)
There is the designation key.
https://wiki.openstreetmap.org/wiki/Key:designation
Could adding designation=snowmobile/ski/atv be a solution?
The thing about leaving things up to interpretation is that different people will have different interpretations. So yes, it is possible. Perhaps you meant to say that, in your opinion, the other interpretation (number 1 in each example) is incorrect. I happen to agree, but floated the question to see if there is consensus or not. I find that the documentation is somewhat ambiguous, and would like to improve it if possible.
I have considered designation= for this purpose. However, it is intended for cases where there is a clear legal classification. For a case where the land manager has designated a trail for a specific transport mode, but no government authority has legally classified it, tagging designation=<transport mode> would seem to dillute the intended meaning of that tag. If the community is open to an expansion of this tag’s meaning, then that could work.
That is the direction I am leaning as well. =designated is kind of weird as an access tag value because it isn’t just about access. Specifying that a way is designated primarily for a certain transport mode is a separate piece of information than specifying who and what is legally allowed to use a way.
well. access=designated is just about “designated under legal access aspects”.
I really would like to understand what you mean by this, but as far as I can tell it sounds like you are saying =designated means the exact same things as =yes – essentially the value serves no purpose.
usually yes, designated means the same as yes, but there are cases where it is more than just yes, I gave an example above of the usage in Germany to distinguish a designated bicycle path from bicycle allowed (also has implications that the designated path may be mandatory)
Yes, @dieterdreist is right. In most of the world =yes is absolutely fine and you don’t need =designated.
It sounds to me like you all are saying that =designated has a very specific meaning (which apparently I don’t actually understand 
) and only applies in certain countries with particular types of laws. Prior to this discussion, that was not my understanding of the meaning. My understanding is based on these descriptions taken from the wiki:
A way marked for a particular use
A preferred or designated route for the class of traffic specified
indicates that a route has been specially designated (typically by a government) for use by a particular mode (or modes) of transport
The value designated is not meant to imply that OpenStreetMap access=* permissions have been automatically “designated” only to that transport mode
The language on the wiki recommends the use of =designated in any situation where a sign indicates that a way is intended for a particular mode of transport. It says nothing about strict legal requirements.
It sounds like you all are saying this is an incomplete description and that =designated is a value that should only be used rarely. If this is in fact the case, it sounds like the wiki should be changed. However, I still don’t understand what the specific cases are where =designated should be used. All I’ve understood so far is that you all say it shouldn’t be used in the examples I’ve put forward!
My primary use case for =designated has been on trails in the backcountry that are managed primarily for one use type, but other uses are also allowed. For example a trail may be managed for horses & stock animals, with hiking also allowed but not the primary use. I would tag this as highway=path + horse=designated + foot=yes. It sounds like you are saying this is not correct, but if =designated is not to be used in a case like this, then what is it for? I’m sure someone will be quick to say that in this case, highway=bridleway + foot=yes should be used instead. However, that type of tagging only works for horse, pedestrian, and bicycle focused ways with bridleway, footway, and cycleway respectively. Other transport modes do not have highway=*way tags like highway=skiway, highway=snowmobileway, or highway=atvway. So highway=path + atv=designated + bicycle=yes is the only way I know of to tag a trail that is managed primarily for ATV use, but where mountain bikes are also allowed secondarily.
If the understanding I’ve developed so far is incorrect, I’d appreciate any further clarification on how the =designated value is intended to be used.
I agree, and think that this describes the problem very well. Right now we have one tag value trying to store two pieces of information - “what is the legal right of access of traffic mode X” and “was this highway=whatever designed for the use of traffic mode X”.
The one absolutely does not imply the other (even before considering “esoteric” modes such as snowmobile). I can think of plenty of places locally (in England) where there is a legal right of bicycle access but it was never designed for and is completely unsuitable for that mode, and plenty of places designed for bicycle (or horse) use where the legal access is only “permissive” - permission can be removed at any time.
Speaking from a region, where this peculiarity of using “desginated” in such a way is a common sight, I give it a try:
There is a body of rules, that govern traffic on public infrastructure. It is not a law, but a directive. It covers a lot of private infrastructure too, eg. parking lots at shopping centers &c. Among other types of streets, for motorists and mixed use, it describes footways, cycleways and bridleways. It contains several rules, that apply especially to that kind of streets (yes, they are true streets.)
Mappers are told in ground school 
to tag those streets “highway=path+foot|bicylce|horse=designated” to tell consumers, that some certain way is not just any old footway, but one, the usage of which is governed by the directive.
That is mostly all there is to this, but it would be easy to collect forum discussions on the subject into a weighty tome. Perhaps I should mention: No sign is necessary for this “designation”, e.g. sidewalks here must not be sign-posted, but of course they are “designated”. Signs not from the directive, eg. green cycle-route markers, do not count.
In the United States, the law on paper, the words on signs, and the laws which get enforced are often three different concepts, which gets more confusing when individual people and businesses also make rules and post signs about various things. There are even privately owned police forces where I live that operate separately from the regular police on behalf of private entities (that is definitely not common everywhere in the US, just an extreme example of something that is a possibility).
I’ve been thinking about this lately because there are quite a few different forms of tagging that could be justified based on different interpretations of the tag. My city has a law on paper that on streets with a speed limit higher than 30 miles per hour, the sidewalks are designated for bicycle use, and bicycles aren’t allowed or encouraged in the roadway. They also paint bike symbols and put up school zone signs and bike symbol signs on roads with a posted speed limit higher than 30 miles per hour. They also don’t enforce speed limits or bicycle rules so in practice people don’t follow any of these things. Going by the law on paper, lots of footways would be bicycle=yes and lots of roadways would be bicycle=no. Going by signs, lots of quite dangerous roads would be bicycle=designated, and almost nothing, if anything, would be bicycle=no. Going by enforcement in practice, nearly every foot way and road way would be bicycle=yes. Going by safety, every foot way and road way would be bicycle=discouraged or bicycle=no, bicycle=designated or bicycle=yes would be only on features completely physically separated from foot ways and road ways.
As I understand it, there are many countries in which a sign saying something is designated for bikes that means that’s also what the law says, so I can see how someone can read the wiki differently if they live in a country like that
There is at least piste:type=* in lieu of highway=skiway.
Note that the piste: prefix is completely orthogonal to the highway and other tags, making it a kind of primary key for this niche use.
Then there is relations route=piste for the typical signposted routes.
Last, there’s also the access tag ski=yes/no/… , but it is seldom used which is to be expected.
For niche practices like atv or snowmobile, I suspect snowmobile=yes or atv=yes is abused for lack of a better dedicated tagging scheme that would simply says ‘have fun on this way with your snowmobile / atv’.
See https://github.com/skoterleder/map-rulesets/blob/master/skoter.mrules#L54
Yes, this is the core of the issue. designated does not make sense as an access value. It seems people have been pointing this out since 2008. We should have a parallel scheme to specify the transport mode a way is designed/intended/designated to be to used by. Something like designated:for=moped;carriage;horse;etc would make sense if data consumers could be counted on to reliably parse semicolon delimited values.
+1, just do it. The designated access is something you can ignore or see as an alternative yes, if it doesn’t make sense to you
I’ve seen some uses of bus=dedicated and while whatever is proposed doesn’t have to follow a scheme that mirrors access exactly, I like the use of the term dedicated. I like the idea of a separate way to show this & would support