[OSM-talk] Highway=trunk : harmonization between countries ?

djakk djakk djakk.djakk at gmail.com
Fri Feb 23 16:12:38 UTC 2018

I know that « trunk »  is country-dependent but why not moving it to a
worldwide definition ? Administrative classification could be moved to
other tags :)


Le ven. 23 févr. 2018 à 16:06, Matej Lieskovský <lieskovsky.matej at gmail.com>
a écrit :

> Greetings
> I'd like to caution against using this system globally. In Czechia, roads
> are formally classified into classes, which influence signage, ref numbers
> and so on. Deploying this system here would make the tag confusing/useless
> and would likely face enormous backlash. I have no problems with using this
> system in countries without a clearly defined road classification, but
> please don't touch the countries where there is no doubt about what class
> any given road is.
> Happy mapping!
> On 22 February 2018 at 16:20, djakk djakk <djakk.djakk at gmail.com> wrote:
>> Hello,
>> I totally agree with you, the definition you provide,
>> administrative-free, tends to the same osm map between countries.
>> djakk
>> Le jeu. 15 févr. 2018 à 19:18, Fernando Trebien <
>> fernando.trebien at gmail.com> a écrit :
>>> Landing on this discussion several months late. I've just heard of it
>>> by reading a wiki talk page [1].
>>> Since 13 February 2009, the wiki [2] criticises highway classification
>>> as problematic/unverifiable. This has also been subject to a lot of
>>> controversy (and edit wars) in my local community (Brazil), especially
>>> regarding the effect of (lack of) pavement.
>>> In trying to achieve greater consensus some years ago, I decided to
>>> seek opinions elsewhere and finally I arrived at this scheme [3] which
>>> I think is very useful, if not perfect yet. It can be easily
>>> summarised like this:
>>> - trunk: best routes between large/important cities
>>> - primary: best routes between cities and above
>>> - secondary: best routes between towns/suburbs and above
>>> - tertiary: best routes between villages/neighbourhoods and above
>>> - unclassified: best routes between other place=* and above
>>> For example, the best route between two villages would be at least
>>> tertiary. So would be the best route between a village and a town or a
>>> city. Parts of this route might have a higher class in case they are
>>> part of a route between more important places.
>>> It surely raises the problem of determining optimal routes. Maybe a
>>> sensible criterion would be average travel time without traffic
>>> congestion. A number of vehicles may be selected for this average -
>>> could be motorcycle+car+bus+truck, or simply car+truck.
>>> Early results in my area [4, in Portuguese] seem promising and have
>>> produced more consensus than any previous proposals. To me, this
>>> method seems to:
>>> - resist alternations in classification along the same road
>>> - work across borders (where classification discontinuities are
>>> expected because each country is using different classification
>>> criteria)
>>> - account for road network topology
>>> - work in countries with mostly precarious/unpaved roads or
>>> without/unknown official highway classes
>>> - work between settlements as well as within settlements
>>> Borderline cases are probably inescapable in any system that does not
>>> use solely criteria that are directly verifiable - from the ground, or
>>> from the law. Maybe, in certain developed countries, the system is so
>>> well organized that merely checking signs/laws is sufficient. That
>>> does not mean it is like that everywhere on the planet.
>>> OSM has so far received a lot of input from communities in developed
>>> countries (mostly Europe, North America and Australia) and hasn't
>>> given much attention to less developed/organized countries. What comes
>>> closest to this is what the HOT Team does, but the judgment of road
>>> classification one can do from satellite images in a foreign country
>>> is much more limited than the criteria that have been raised in this
>>> thread so far.
>>> I wouldn't endorse tags such as maxspeed:practical due to lack of
>>> verifiability (it should be obvious that different types of vehicles
>>> would achieve different practical speeds). It is better to use the
>>> legal speed in maxspeed=* and describe the practical reason for a
>>> lower speed using surface=*, smoothness=*, and, who knows, maybe the
>>> not yet approved hazard=* [5] (though that is intended for signed
>>> hazards, not subjective/opinionated hazards).
>>> For the sake of long-term sanity, I also wouldn't mix the purpose of
>>> one tag with the purpose of other tags. To describe the surface, there
>>> is surface=*, smoothness=* and tracktype=*. To describe access rights,
>>> there is access=*, foot=*, bicycle=*, motor_vehicle=*, etc. To
>>> describe legal speed, maxspeed=*. To describe curves, there's
>>> geometry.
>>> Purpose, perhaps, is the main issue. What is the purpose of highway
>>> classification? Is it to save us the work of adding extra tags? Is it
>>> to allow the renderer to produce a cleaner output at low zoom levels?
>>> Is it to allow routers to assume default speeds? Maybe to guide their
>>> routing heuristics? Is it to express some sort of importance? If so,
>>> by which perspective - urbanistic, traffic engineering, movement,
>>> commercial value, cultural/fame, historic, some combination of those?
>>> Should the purpose be the same in every country?
>>> It may be interesting to also discuss the classification adopted by
>>> other maps. I don't have a reference for Google (originally TeleAtlas)
>>> or Here.com (originally Navteq), but Waze publishes its per-country
>>> road classification criteria in its wiki. [6-16]
>>> [1]
>>> https://wiki.openstreetmap.org/wiki/Talk:Tag:highway%3Dtrunk#change_.22high_performance.22_to_.22high_importance.22
>>> [2] https://wiki.openstreetmap.org/wiki/Verifiability#Problematic_tags
>>> [3]
>>> https://wiki.openstreetmap.org/wiki/User:Ftrebien/Drafts/Generic_highway_classification_principles#Schematic_diagram_and_general_comments
>>> [4] https://forum.openstreetmap.org/viewtopic.php?pid=674296#p674296
>>> [5] https://wiki.openstreetmap.org/wiki/Proposed_features/hazard
>>> [6] https://wazeopedia.waze.com/wiki/USA/Road_types
>>> [7] https://wazeopedia.waze.com/wiki/UnitedKingdom/Roads#Road_types
>>> [8] https://wazeopedia.waze.com/wiki/Canada/Main_Page#Road_Types
>>> [9] https://wazeopedia.waze.com/wiki/Commons/Road_Types/India
>>> [10]
>>> https://wazeopedia.waze.com/wiki/Brazil/Como_categorizar_e_nomear_vias
>>> [11]
>>> https://wazeopedia.waze.com/wiki/Germany/Kartenlegende_(Deutschland)
>>> [12] https://wazeopedia.waze.com/wiki/France/Classification_France
>>> [13] https://wazeopedia.waze.com/wiki/Italy/Tipologia_delle_strade
>>> [14] https://wazeopedia.waze.com/wiki/Indonesia/Panduan_Tipe_Jalan
>>> [15] https://wiki.waze.com/wiki/%E9%81%93%E8%B7%AF%E7%B1%BB%E5%9E%8B
>>> [16]
>>> https://wiki.waze.com/wiki/%E3%80%8C%E9%81%93%E8%B7%AF%E7%A8%AE%E5%88%A5%E3%80%8D
>>> --
>>> Fernando Trebien
>>> +55 (51) 99962-5409 <+55%2051%2099962-5409>
>>> "Nullius in verba."
>>> _______________________________________________
>>> talk mailing list
>>> talk at openstreetmap.org
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