[Tagging] Can highway=cycleway be limited to MTB?

[Mark Wagner]

On Thu, 2 Apr 2020 10:53:57 -0400
Kevin Kenny <kevin.b.kenny at gmail.com> wrote:

> On Thu, Apr 2, 2020 at 5:12 AM Volker Schmidt <voschix at gmail.com>
> wrote:
> >
> > If a highway is mtb:scale=2 it is definitely not a cycleway. It is
> > a highway=path with mtb:scale=2 If this were to encounter a
> > "cycleway" with mtb:scale=2 , I would consider this an error and
> > retag it as highway=path without hesitation.
> >
> > I agree, that this is not explicitly stated in the bicycle wiki
> > page, and should be added there, but I would assume that this is
> > the common understanding. Anything else would cause major problems
> > with the huge stock of existing highway=cycleway in OSM that have
> > no mtb:scale tag. Routers for non-MTB bicycles would all need to
> > change and evaluate the mtb:scale tag.
> >
> > There is already a similar problem with the OpenCycleMap rendering
> > in the sense that it renders a dedicated cycle path in the same way
> > as a path with bicycle=yes. This has the effect that many MTB
> > friends have added bicycle=yes to "normal" hiking paths to make
> > them appear as MTB friendly on the map, but also with the problem
> > that when I look at that map I wrongly see a cycle paths where I
> > would never be able to pass with my loaded touring bike.
> >
> > Please keep paths that can only be used by MTB clearly different
> > from cycleways that can be used non-MTB bicycles.  
> 
> A key issue is that mtb:scale can't be the only indication. Otherwise,
> we're falling into a trap - which has been a common trap in the past.
> It's a trolltag https://wiki.openstreetmap.org/wiki/Trolltag - a
> second tag that negates or massively changes the meaning of another
> tag. "This isn't what you were expecting of a highway=cycleway: it's a
> wilderness trail for highly skilled and adventurous MTB riders!"

But "highway=path, bicycle=yes" has the same issue.  From a legal
standpoint, this is a "highway=path, foot=yes, bicycle=yes, horse=yes,
ski=yes, snowmobile=yes".  From a practical standpoint, however, it's
"ski=yes, snowmobile=yes, foot=difficult, bicycle=carry,
horse=nope".

https://help.openstreetmap.org/upfiles/RoughTrail.jpg

There isn't any top-level tag to indicate that trees have fallen across
the trail creating a waist-high barrier, and that it's only easy to
traverse once there's three feet of snow on the ground.

-- 
Mark