[OSM-talk-be] trunk crossroads and cyclerouting

[Ben Laenen]

Klaas Gadeyne wrote:
> This way is currently tagged as trunk_link
> <http://wiki.openstreetmap.org/wiki/Link_(highway)>.  However, (at
> least in Belgium) trunk roads are prohibited for bicycles.

Well, yes and no. Yes for 99% of trunks in Belgium, but there are exceptions, 
particularly at crossroads where one wouldn't downgrade small pieces of road. 
Take for example a crossing between two dual carriage roads, one trunk, the 
other primary: you wouldn't split the trunk at the crossing to downgrade it on 
that little bit to primary.

I wouldn't use links for these bits either: links are primarily for ramps (op- 
en afritten) to the road, like those on motorways.

> So it seems like trunk_link ways are also "bicycles prohibited".  Does
> anyone have a suggestion/thought on how to fix this?
> 
> - Changing trunk_link into primary_link seems weird (and only solves
> the problem locally)

I usually tag these small ways between two lanes of a dual carriage road with 
the same classification of the crossing roads, in this case 
highway=unclassified. But there's no strict rule on this AFAIK, even though we 
could really use one...

(Also, preferably keep this little way as a separate way, i.e. don't join with 
the crossing roads)

> - Altering the "bicycles prohibited behaviour" of trunk_link sections
> seems to be an option, but I don't know if this is the best thing to
> do and whom to contact for that?

It's just something we as osm-be agree on (or not), routers etc should follow 
what we agree on (but nowadays often don't of course since they only have one 
set of rules for the entire world).

In the best case you'd have other tags on the road telling if it blocks access 
or not, like
* motorroad=yes for "autoweg" (original meaning for trunk in Belgium, but 
we've added other roads that block access to pedestrians and cyclists to 
trunk, and on the other hand have "autowegen" that aren't classified as trunk)
* foot=no, bicycle=no, moped=no if there are traffic signs for these

If all trunks had these tags it'd be safe to allow pedestrians and cyclists on 
trunks *by default*, but that's not the case by far, so we need some other 
single magic tag that says this. I can only think of motorroad=no for this.

Greetings
Ben