[Talk-us] Alaska Highway AK-2 tagging

[Bradley White]

> Long term, it would be nice to separate these notions and have some
> highway:importance key for that, and leave the road type notion that
> separates primary/trunk/motorway alone (or move it to some other tag,
> and get rid of highway=trunk and highway=motorway).

Ideally, this is what 'highway' is already supposed to represent
(https://wiki.openstreetmap.org/wiki/Proposed_features/Highway_key_voting_importance).
The debate fundamentally is over whether roads built to "expressway"
standards are de facto important enough to warrant being their own
class of importance, in the same way that freeways are in the US
(given that the US has a national interstate system). I think there
are convincing cases for both tagging schemes, but that ultimately we
need to make a decision as a community, since using both is ambiguous
and confusing.

> I guess you are suggesting to add highway=expressway to have expressway
> mean "sort of motorway but not quite" and change trunk to be "very
> important".  I am afraid that with so much established tagging the only
> reasonable approach to orthogonalization is to adopt two new tags for
> the things in question and deprecate the old way, allowing for a long
> and messy transition.

If 'trunk' became defined as "most important roads", I would suggest
adding a tag like 'expressway=yes/traditional/super_two/...', default
'no', to indicate the built design of the road. There has already been
such a proposal for a while, though currently abandoned:
https://wiki.openstreetmap.org/wiki/Proposed_features/Expressway_indication