[Talk-us] Update on potential highway classification reform

[brad]

I think the fundamental problem is that we have too many tags for a 
functional classification scheme.   If trunk isn't going to be a limited 
access highway then perhaps it's redundant.  Another option is to remove 
unclassified.   Since we probably won't remove a redundant tag with a 
history, the renderers need to sort out the overlap.

This is my take:
Looking at the roads for my state of Colorado (& recently traveled areas 
in UT, AZ, NM) I think the highways could be reasonable be tagged as:

  *     US highways: Primary
  *     State highways: Secondary
  *     County Roads: Tertiary, Unclassified, or Residential
  *     Forest Service & BLM roads: Unclassified or track, maybe a few
    tertiary.

Using this criteria, it seems to meet the OSM wiki spec of 'The most 
important roads', 'The next most important roads', etc. There may be 
exceptions, but nothing seemed obvious to me inspecting my current home 
area, or previous home areas, or places I've driven.

You could also classify as US highway:Trunk, CO highways:Primary.    
That would work, but then the lower classes are difficult to classify 
(too many choices).  Perhaps then unclassified is redundant.

I noticed that the mapper who lit off this email chain, oregonian3, 
recently changed many roads in Colorado (in addition to the roads in 
northern CO that Mike T noticed) from primary to trunk.   At least one 
of those was changed back to primary by another mapper.

Early in the email trail someone pointed out the the OSM carto issue 
with a trunk road disappearing when it changed to primary.   I think 
that is a problem with OSM carto, a trunk and a primary should show up 
on the same level.


On 5/17/21 3:54 PM, Brian M. Sperlongano wrote:
> Hi Folks,
>
> I'd like to provide the community an update on the work that's been 
> happening to improve the current state of US highway classifications.  
> Following the recent talk-us threads, there were extensive debates in 
> Slack, especially in the #local-us-northeast channel, about how to 
> better apply the highway classification values with international 
> norms, especially the trunk classification, which seems to be the most 
> challenging.
>
> There was a strong consensus initially amongst New England mappers 
> that the highway classifications should be used in a way that's 
> consistent with the connectivity importance of various roads.  There 
> was also a general agreement that documenting state-specific highway 
> classification criteria was important for preventing edit wars as well 
> as documenting edge or unusual cases and the rationale behind them.
>
> The outcome of those discussions was the following wiki page[1], which 
> offers general guidelines that can be applied in state-specific ways 
> to come up with criteria that mappers can follow.  As part of these 
> discussions, local mappers have been drafting state-specific pages 
> that would implement these general guidelines.  State-specific 
> criteria have been drafted so far for: MA, MS, NH, RI, VT, TX, and WA.
>
> In order to demonstrate what the new classification would look like on 
> the map, the New England mappers have put together a temporary live 
> demo[2] which shows what this new arrangement would look like at the 
> motorway and trunk level.  This demo is set up to show the proposed 
> "new" highway classification alignment in *four* New England states 
> only: VT, NH, MA, and RI.  The rest of the country is shown with no 
> change to highway classification.  In addition, this demo map is 
> rigged to show motorway/trunk at their normal zoom levels, but 
> suppress highway=secondary until zoomed in close, in order to 
> specifically examine the motorway/trunk network in better detail.
>
> Links:
>
> [1] 
> https://wiki.openstreetmap.org/wiki/United_States/Highway_classification 
> <https://wiki.openstreetmap.org/wiki/United_States/Highway_classification>
> [2] http://74.97.52.189:6789/openstreetmap-carto/#7/43.250/-70.756 
> <http://74.97.52.189:6789/openstreetmap-carto/#7/43.250/-70.756>
>
> I offer this update as an invitation to further collaboration on how 
> we might better map highway classifications in the US.
>
> _______________________________________________
> Talk-us mailing list
> Talk-us at openstreetmap.org
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