[Tagging] Clarification unclassified vs residential

[Mark Wagner]

On Wed, 20 Feb 2019 11:30:07 -0300
Fernando Trebien <fernando.trebien at gmail.com> wrote:

> On Wed, Feb 20, 2019 at 10:52 AM Greg Troxel <gdt at lexort.com> wrote:
> > The real problem is that if unclassified is more important than
> > residential, what to do with roads that do not merit unclassified
> > but do not have primarily residential landuse?  
> 
> That's why I think classification should be done by primary
> function/purpose, not by a fuzzy (and controversial) concept like
> importance. "Importance" begs the unanswered questions: important for
> what? for whom?

Here in Washington State, there are two possible "non-fuzzy"
classification schemes:

1) By usage rules: Motorway/arterial/other.  This isn't very
fine-grained, and doesn't give you a way to distinguish Sprague Avenue
(five lanes one-way) from Queen Avenue (two-way, no lane markings) from
WA-20 (major cross-state highway) from WA-127 (exists only to avoid a
hundred-mile detour when crossing the Snake River).

2) By operator: Interstate highway/US highway/state highway/county
road/other.  This is fine-grained but misleading: for example, WA-520
(a state highway) is a multi-lane divided grade-separated high-speed
controlled-access road -- in short, an Interstate in all but name.

(There's also the state highway department's internal highway
classification system that maps reasonably well to OSM's system, but
you'd have to copy it from their maps -- there's no on-the-ground
evidence that something is an "Urban Major Arterial" or a "Rural Minor
Collector".)

> > Finally, I'd suggest in the US treating unclassified and
> > residential as exactly the same in importance, because we have no
> > real notion of unclassified roads like the UK.  
> 
> Do you have any locally-defined highway system that approximately
> matches the idea of "a system of highways that generally connects
> place=hamlet"?

That would be the state highway system: nearly every incorporated
community and most of the unincorporated ones are served by at least
one state highway.  But see the above examples for why calling these
roads "unclassified" is a bad idea.

(And note that all of the above is only fully applicable for Washington
State.  Other states will have other systems, though at least in the
western United States, they don't vary by much.)

-- 
Mark