[Talk-us] US Trunk road tagging

[Paul Johnson]

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.
>>
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