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

Fernando Trebien fernando.trebien at gmail.com
Sun Feb 25 19:53:39 UTC 2018

On Sat, Feb 24, 2018 at 6:00 PM, Lester Caine <lester at lsces.co.uk> wrote:
> I think the main problem is that there are well established guidelines for
> various areas on mapping data at both country and region level but in may
> cases even those rules do not harmonize. We need the several levels of
> highway that are currently accurately mapping UK roads, but other areas of
> the world do not need that degree of classifications ... so they just don't
> use the ones that are not appropriate ...

highway=trunk is currently defined like this in the wiki: "high
performance or high importance roads that don't meet the requirement
for motorway. In different countries, either performance or importance
is used as the defining criterion"

So, is it "either" performance "or" importance, or "only one" of those
two? It's hard for a local community to agree on which factors count
when the definition is vague. What is missing is establishing the >>
fundamental purpose << of classification of motorised ways at the
global level. Suppose that "performance" is the desirable meaning.
That suggests that classification should be done based on physical
qualities of the road (leading to fragments of alternating class). If
instead "importance" is the desirable meaning, we still need to know
what makes the road important: relative or absolute traffic volume?
Economics? Planning? Administrative level? Access rights of
non-motorised modes? Is it the road's "function" as in "functional
classification" [1][2]? Is it the road's suitability for freight [3]?

Suppose that "freight" should be an important aspect for the trunk
level for any country. That means that trunks must be suitable for
truck traffic. That would make the following at least trunk (some
might be motorway):
- most US highways and interstates (it would be the National Freight
Network [4])
- most national AND state highways in Brazil, except those with load
restrictions and those that are unpaved and in poor condition
(including main routes between several state capitals)
- state highways in India (though perhaps not all of them, due to
conservation problems - like in Brazil)

[1] https://comparativegeometrics.wordpress.com/2013/05/16/how-many-levels-in-a-road-hierarchy/
[2] https://wiki.openstreetmap.org/wiki/User:NE2/classification_FAQ#Why_can.27t_we_use_functional_classification.3F
[3] https://en.wikipedia.org/wiki/Trunk_road
[4] https://ops.fhwa.dot.gov/freight/infrastructure/nfn/index.htm

Fernando Trebien
+55 (51) 9962-5409

"Nullius in verba."

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