[Talk-us] Trunk

Paul Johnson baloo at ursamundi.org
Sat Oct 14 04:21:03 UTC 2017

On Fri, Oct 13, 2017 at 10:19 PM, Bradley White <theangrytomato at gmail.com>

> > Message: 4
> > Date: Fri, 13 Oct 2017 21:24:20 -0500
> > From: Paul Johnson <baloo at ursamundi.org>
> > To: OpenStreetMap talk-us list <talk-us at openstreetmap.org>
> > Subject: Re: [Talk-us] Trunk
> > Message-ID:
> >         <CAMPM96rCyLRupvPJk=cBtqfS2U6NrDj5SmooBUYV33SSDFRCHw at mail.
> gmail.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > On Fri, Oct 13, 2017 at 9:10 PM, Bradley White <theangrytomato at gmail.com
> >
> > wrote:
> >
> > I reject this because it will lead to an overemphasis of relatively
> smaller
> > roads.
> I disagree, and would be more inclined to say that this is exactly
> what we need. The US has loads of primaries, and fairly so, but this
> tends to bury the more important among those.
> Even if there is a strict, verifiable criteria set for what
> constitutes an expressway, I don't think it's what we should use to
> determine the importance of a road, and thus use of the trunk tag. I
> don't think it's a term that, in the US, has meaning to the average
> non-highway-engineer citizen in the same way that a freeway does.

This is not an insurmountable barrier; education isn't that difficult for
basic definitions.

> Other countries that lack a clear expressway system, like Canada and
> the UK, use the trunk tag (successfully) in the same way that I am
> suggesting the U.S. use it. The UK/Canada system and the central
> Europe system both adopt the tag in a way that makes sense for the
> road network they have. We are trying to shoehorn the central European
> tagging system into our country when, to me, it makes more sense to
> use the UK/Canada system. Why does it benefit map users in the US to
> set the second most important class of roads equivalent to roads that
> are physically an expressway, especially when this could easily be
> tagged separately?

The concept of expressway and freeway are reasonably well known concepts;
it makes a lot of sense to map trunk and motorway to those concepts.
Granted, there is fuzz between a big-ass primary and a low-grade
expressway.  And there's some difficulty on where to draw the break to
motorway on trunks that mix junctions and interchanges (like WA 500 between
I 5 and Fourth Plain Boulevard.

Even a lot of renderers make this same assumption:  mkgmap maps trunk to
Garmin's concept of expressway and motorway to freeway.  Osmand, easily the
most popular data consumer for OpenStreetMap, makes the same assumption (to
the point that most of it's map painting styles, the only differentiation
between trunk and motorway is a color pallette shift).  It really wouldn't
hurt the US community to have a "come to Jesus" moment on this,
particularly when using the MUTCD definitions for expressway and freeway as
qualifiers for trunk and freeway, makes this relatively easy.  The
corollary to "don't tag for the renderer" is "don't break the renderer".
Highways without access control being excluded from trunk or motorway isn't
an intrinsically bad assumption to make.  Especially if we come to
agreement on that, we can start having a productive talk on how to make
carto not suck for Americans without breaking it for everyone else.
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