[Talk-us] Trunk

Paul Johnson baloo at ursamundi.org
Fri Oct 6 17:59:40 UTC 2017

On Fri, Oct 6, 2017 at 12:17 PM, Kevin Kenny <kevin.b.kenny+osm at gmail.com>

> On Fri, Oct 6, 2017 at 10:00 AM, Richie Kennedy
> <richiekennedy56 at gmail.com> wrote:
> > Perhaps I should make it clear that I am willing to pull a **full NE2
> > defense** of the position that a controlled-access Super 2 is properly
> > tagged as motorway.
> Do we have differing definitions of a Super Two?

I believe we're all on the same page that a super-two type situation is a
controlled access, single carriageway, where that single carriageway
operates in both directions, typically two lanes (though there may be
additional lanes for short distances to facilitate merging, exiting or at
toll plazas).

My personal threshold for 'motorway' is that potential conflicting traffic
> is
> grade separated.

Would you consider oncoming traffic as conflicting?  That's the crux on the
super-two debate.  I would consider at least two lanes each way,
free-flowing, controlled access, and at least two carriageways as the
minimum threshold for motorways.  Limited access, at-grade intersections,
single carriageway, this all would be more characteristic of trunks to me.

> I'm not comfortable with tagging as 'motorway' any road that has
> at-grade opposing
> traffic. (Example: US 7 in between Arlington and Rutland, Vermont.
> Access is fully controlled, but there is
> no grade separation between opposing lanes. Climbing lanes are provided on
> steep grades, but passing in the oncoming lane is lawful in some straight
> and
> level sections.)

I've made a one-off exception in the case of US 412 on Diamond Head, mostly
because a single, lone, relatively unused junction remains at grade out of
over 160 km of motorway largely due to terrain limitations.  There's a few
similar situations with driveways and the occasional extremely minor road
going directly into bona-fide interstates in Utah.  And of course, the
traffic lights to let ships through the drawbridge on I 5, literally the
only traffic light on that road for it's entire three state run.  So there
is an edge case to motorways where every attempt has been made to ensure
traffic is free flowing and conflict-free, but some single point couldn't
be properly eliminated.

I'm not planning to tag or retag anything; I don't have a dog in this
> particular
> fight. I write this message as a data consumer. But I think that the
> tagging seen
> in http://www.openstreetmap.org/#map=19/41.88704/-73.76900 is utterly
> nonsensical. What the Sam Hill does it mean to have a 'motorway' that
> you tag as 'trunk' for barely the width of the intersection so that you can
> put a grade crossing on it? It might silence a warning about placing
> a grade crossing on something as a motorway, but there's no useful
> information to a driver.

It's worse than useless - it raises the false expectation that the road is a
> motorway when it is not. It has grade crossings; it has narrow shoulders
> (not
> necessarily a disqualifier); it has the same speed limit as primary roads
> in its vicinity. It's a trunk road, or would be if we had designated trunk
> roads in the US. Tagging it as a motorway encourages unsafe driving,
> and at the threshold of an intersection is not sufficient notice to drivers
> of a downgrade.

This reminds me of WA 500 between I 5 just north of Officer's Row in
Vancouver, WA; and Fourth Plain near the Sifton neighborhood. It really
should be trunk for that whole length due to the mix of at-grade and grade
separated intersections and abrupt end on a surface street (and even after
the last intermediate intersections at 42nd and at Stapleton get grade
separated, I'd still be wary of calling any part of that a motorway until
something's done about the end at Fourth Plain, because it does
significantly interrupt traffic coming from the expressway part, literally
opposite what you would expect out of a freeway, particularly when it's so

Trunk is basically everything that's more freeway-like than a boulevard,
but not quite a freeway.
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