[Talk-us] US Trunk road tagging

[MoiraPrime]

I personally think we should do the following

1. Trunks should connect to other Trunks or a Motorway on both ends if possible. No Isolated islands.

2. Motorways should be longer than 1 mile, be an incomplete under-construction interstate, or be connected to another motorway. Random short island sections of interstate existing solely because someone thinks an interchange meets motorway quality should not exist (which is a repeated topic in the OSM US Slack).

3. Trunks should be important roads that fill in gaps in the Interstate system between two large cities. This can be 4 lane US highways, but it can also be 2 lane US highways, 4 lane state highways, you get the idea. The main idea is that the road is filling an important gap in the interstate system.

Open to thoughts on this. It was on my mind all last night while I was dozing off to sleep.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Wednesday, May 5th, 2021 at 2:07 PM, Paul Johnson <baloo at ursamundi.org> wrote:

> Well, that'd still be incorrect tagging. All freeways are expressways
> 

> but not all expressways are freeways. If there's a question on
> 

> whether something is really a freeway or not, it shouldn't get
> 

> highway=motorway.
> 

> On Wed, May 5, 2021 at 1:38 PM marcel at dejean.nyc wrote:
> 

> > 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.
> > 

> > 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.
> > > 

> > > Talk-us mailing list
> > > 

> > > Talk-us at openstreetmap.org
> > > 

> > > https://lists.openstreetmap.org/listinfo/talk-us
> 

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> 

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> 

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