[Talk-us] US Trunk road tagging

[marcel at dejean.nyc]

Regardless of what the criteria for any given road classification are, it
seems basic to me that the classification should apply to the whole road,
or at least a whole functional section of it, where many users are going to
use only parts of that road meeting the criteria. So a road which is mostly
highway=trunk because of fronting uses or traffic lights does not become a
highway=motorway every time it passes over a bridge
<https://www.openstreetmap.org/way/361097130>.

On Wed, May 5, 2021 at 11:29 AM Paul Johnson - baloo at ursamundi.org <
ra+pfpiagvmxbrpqempfwbozqs at simplelogin.co> wrote:

> On Tue, May 4, 2021 at 10:31 PM Bradley White <theangrytomato at gmail.com>
> wrote:
> > Here are some counterpoints as to why I'm not completely on board with
> > "importance" tagging yet:
> >
> > The issue of floating "trunk" segments on the main slippy map is
> > awful, agreed.
>
> Aesthetics aside, such floating chunks does reflect the ground truth.
> It's not OSM's fault that highway departments, especially in rural
> parts of the country, prefer grand islands of expressway to nowhere.
> We just document it.
>
> > However, I think this is at least in part a
> > cartographical compromise rather than a data/categorization problem. I
> > think a US-oriented map styling that weighs US/state route
> > designations more heavily than OSM classifications when deciding
> > rending prominence would result in much less arguing about this.
>
> Which, thankfully, is already reasonably attainable by rendering based
> of network tags of road route relations.
>
> > I also worry that adopting a strictly "importance"-based definition
> > for trunk roads will induce an over-zealous use of 'motorway', a
> > problem the US already has (trying to tag every single time a divided
> > road has any kind of grade separation as 'motorway' is bad tagging,
> > but prevalent around the US).
> >
> > I think the fact that so many US mappers
> > are so eager to tag every singular divided grade-separated interchange
> > as 'motorway' (regardless of what comes before or after the
> > interchange) speaks to the fact that many mappers expect to see a
> > rendering distinction between a plain-old highway and a more
> > freeway-like road. Removing an in-between category will exacerbate
> > poor use of the 'motorway' tag, unless stricter guidelines are put in
> > place for 'motorway' use in tandem.
>
> This is particularly prominent on stretches of interstate highways
> that aren't really freeway but signed as interstates.  Between the
> international border and the last exit before the border on both ends
> of Interstate 5 come to mind as "not a freeway but is an interstate".
> There's also decent length chunks of interstates that are not
> freeways, with multiple intersections in a row in the desert west
> (even if they are dual carriageway and fast, and most of the
> crossroads get about the same traffic annually as my driveway, they
> have at-grade intersections).
>
> > This is the crux of the argument to me: is a road being constructed to
> > an "expressway" standard significant enough to bestow its own
> > classification in the importance hierarchy?
> > I'm *slightly* more convinced that the answer is yes. If we accept
> > freeways as being, strictly by physical construction & with no regard
> > to the importance of the route they carry, important enough to warrant
> > its own class, then I don't think it's a big stretch to have another
> > category just beneath it for roads a layperson might call a freeway,
> > but that a roads geek knows is not. I certainly know of some freeways
> > that are nowhere near important enough to need rendering on low zoom,
> > but it's a compromise we accept.
>
> I think it might also be time to consider formally introducing lower
> classes of roads.  Quaternary, quintenary, etc; this would help with
> borderline absurd situations like the ~10-network (in addition to US
> and interstate) Texas state highway system.
>
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