[Tagging] "Feature Proposal - RFC - bicycle=use_cycleway

Pee Wee piewie32 at gmail.com
Thu Nov 14 19:12:25 UTC 2013


A question and some remarks


Considering  routers and not breaking routing.

A few of you have made remark concerning breaking schemes and routers
getting in to problems. I do not understand this. Ronnie Soak e.g. wrote “I
would prefer an additional tag over a replacement for bicycle=no, as this
would allow an easier migration due to not breaking older routers.”

The definition of the tag is: This is a highway (i.e. tertiary) with a
classification
that allows cycling
generally<http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Access-Restrictions#Germany>
*without* "bicycle forbidden sign" and *with* a parallel compulsory
cycleway.

This means that currently these roads (except NL) do not have a bicycle=no
or a bicycle=yes tag.  So this tag is NOT  replacing any previous tag. If
it would replace a current bicycle=no I propably would not have proposed
any new tag at all ;-)  The absence of any “bicycle=” tag is the reason for
this proposal.


So if these roads would be tagged with a bicycle=use_cycleway nothing
changes in routers because they don’t know the tag and it does not replace
any current tag. The first router that picks up this new tag will be able
to propose a good route.  So why would routers have a problem with this new
tag?


Restriction instead of use_cycleway

Some have said not to be happy with the name “use_cycleway” and instead use
something with “restriction” etc.   It is true that it is a restriction but
the only reason for this restriction is the fact that there is a parallel
compulsary cycleway. If this cycleway would not be there, there would not
be restriction.  So there is a clear relation between the cycleway and the
restriction on the road. I think it is best if we have a tag that refers to
the cycleway. This way we and routers know that the restrictions are based
on (country specific)  rules.



Sign on one “highway” has access implication on an other “highway”

The traffic administration want to keep signs as simple as possible and
right they are. Not only to keep overview but also because it is undoable
to have signs for every exceptional vehicle or means of transportation.  That’s
why only the most common vehicles are on access traffic signs. If you
drive/ride an exceptional vehicle you are supposed to know where to ride
based on signs with only most common vehicles on it. I think this proposal
is about a more or less strange situation. Most traffic signs we see have
access information about the road on which it is placed.  In this situation
it is clearly different. Access information on the cycleway (compulsory)  means
that an ordinary bicycle has to use the cycleway (in most cases) and has no
access to the main road. As far as access is concerned the 2 are linked.
This would not be the case if the administration would have come up with a
new traffic sign on the parallel road saying “in these  situations you may
use this road but apart from that, use the cycleway”.  In that case I am
sure we would have come up with a tag somewhere in between bicycle=no and
bicycle=yes.


2013/11/14 Ronnie Soak <chaoschaos0909 at googlemail.com>

> Robert argued here that country-specific restrictions should be always
> expressed by tags so that routers don't need to know those specific
> rules/laws.
> He gave the maxspeed tags as an example, which we explicitly tag even if
> they are based on implicit laws.
>
> I think this generalization is goes too far.
>
> For the access tags (and we do discuss access tags here), it is common
> practice to have country-specific defaults on certain highway types as
> listed in the wiki [1] and only tag what contradicts those defaults.
> I don't see why it would be needed to switch that to explicitly tagged
> values. Opposed to maxspeed, we are talking a large set of different tags
> here where both tagging as well as legislation is in constant change.
>
> Based on these asumptions, I would argue that it would be enough to
> specify if a compulsory exist or not and leave the details of which type of
> vehicle can under which conditions use the road or not to the router, which
> should implement those based on national defaults. So at least the
> legislation changes can be implemented at a central point.
> (This is already the default, so no additional change needed for that.)
>
> I would prefer an additional tag over a replacement for bicycle=no, as
> this would allow an easier migration due to not breaking older routers.
> (This is why I would vote 'no' on the proposal.)
>
> I would also say that stating that there IS a compulsory cycleway is a
> first step, but not enough. To check for certain conditions (width,
> direction, reachable destination, obstacles, surface), the router would
> need to know WHICH way is the compulsory cycleway.
> We can either do this with a relation combining the highway and the
> cycleway(s) or with tags and self-created references. I would clearly
> prefer the first.
>
> I think neither storing all the information needed for those decissions in
> the highway tags (instead of the cycleway tags) would be a doable
> workaround nor pre-interpreting them by the mapper and
> tagging the result on the highway. As stated above, those interpretations
> would be based not only on (ever changing) local administration but also on
> very subjective opinions.
> As a user, I'd rather have those opinions baked into the routers I can
> chose, not in the map data all routers have to use.
>
> My 2 cents,
>
> Chaos
>
>
>
> [1]
> https://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Access-Restrictions#Germany
>
>
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>
>


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