[Talk-us] Trunk

[Mark Bradley]

> Date: Fri, 6 Oct 2017 12:59:40 -0500
> From: Paul Johnson <baloo at ursamundi.org>
> To: OpenStreetMap talk-us list <talk-us at openstreetmap.org>
> Subject: Re: [Talk-us] Trunk
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> On Fri, Oct 6, 2017 at 12:17 PM, Kevin Kenny <kevin.b.kenny+osm at gmail.com>
> wrote:
> 
> > 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 short).
> 
> Trunk is basically everything that's more freeway-like than a boulevard, but not quite
> a freeway.
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Like many topics on this mailing list, this topic keeps popping up from time to time and never gets resolved.  When I first joined OSM about three years ago, I read the Wiki topics about road classifications, including those specific to the US.  There are a lot of comments on there, going back many years.  The issue was not resolved then, and it never gets resolved every time it is brought up on the mailing lists.  In my opinion, this issue is so broad and varied, a consensus will never be reached this way.  I believe a different procedure will be required.

Mark