[Tagging] New proposal: Obligatory tagging of oneway on motorway_link

[Shawn K. Quinn]

On Thu, 2015-09-10 at 14:20 +0200, Joachim wrote:
> I drafted up a proposal about oneway=* for highway=motorway_link.
> Please comment.
> http://wiki.openstreetmap.org/wiki/Proposed_features/Motorway_link_obligatory_oneway
> 
> Proposal:
> Define on the wiki page of highway=motorway_link that oneway=* must
> also be tagged for every motorway_link. If not tagged, the oneway=*
> status of this way is undefined.

Though I agree in principle with the idea of making tagging more
explicit, how big of a practical concern is this? i.e. how many times in
the real world is motorway_link a two-way road?

> - For rendering purposes ways with undefined oneway should be
> displayed like the default, i.e. without oneway arrows.

This I support...

> - For routing purposes it is recommended to not route over ways with
> undefined oneway since any assumption may be wrong and it would be
> best to correct the data.

This I don't. In a lot of cases the likely direction of a motorway_link
can be inferred by the angle of the junction, even if not explicitly
tagged.

> - In map editors undefined oneway should be displayed as tagging
> error.

This makes sense, but will cause a fair amount of grief while the
existing data is fixed.

-- 
Shawn K. Quinn <skquinn at rushpost.com>