[OSM-talk-be] wiki highway conventions

[Ben Laenen]

On Friday 28 December 2012 00:22:17 Glenn Plas wrote:
> But the general wiki (which is probably USA based if I'm not mistaking
> here) does say so:
> 
> http://wiki.openstreetmap.org/wiki/Tag:highway%3Dprimary
> 
> There is not much room for interpretation except 'large' definition.

It's not really any country based. The definition is as broad as possible, and 
every country makes its own rules.


> But I understand if you drive over R22 you would classify it primary
> (although it has 4 lanes divided by a central barrier, not 2). That
> would be a trunk to me as it connect to the E19 complex in Vilvoorde.

There are cycleways, so no trunk...


> As a subnote, the N211 which belongs to that complex goes primary until
> the city center, that is wrong imho matched against the theory.

Yeah, N211 should be secondary east of the R22.

West of the R22: makes sense as primary. Strictly following the rules it 
should be secondary of course, but this is one of those possible exceptions.


> > I guess someone did something similar in Vilvoorde with the R22. Whether
> > that should be done, not really sure here.
> 
> That's why I bring it up as I'm not totally sure myself, but when I'm
> not sure, I check the wiki ...

And of course the wiki isn't exactly the best reference for it :-) The 
"definition" has been slowly adjusted on the mailing list for example, but we 
can't expect everyone to know the entire history of course...


I guess I'll make a small summary with some examples (limiting to 
trunk/primary/secondary):


* trunk: "expressways", prohibited for pedestrians and cyclists. May be signed 
with F9 (motorroad), but not always. Not all roads with F9 are trunks (e.g. 
tunnels or bridges if the road it is part of isn't classified as trunk)

* primary: Nx or Nxx roads

* secondary: Nxxx roads (or P roads)


Exceptions to primary/secondary above: 

* ringways (usually R roads, but can be N roads): classification from highest 
classified road that connects to it. Inside R road primary road becomes 
secondary if the ringway deviates the traffic between the *primary* roads. 
Secondary roads stay secondary inside ringways (they don't become tertiary) 
(*).
e.g. R13 http://osm.org/go/0ErVXu0



* everywhere it makes sense... When a road without number connects two parts 
that do for example, or any other weird situation you may encounter.
e.g. Corbiestraat as primary http://osm.org/go/0ErYW5cL
Plezantstraat as secondary (no road number) http://osm.org/go/0Ej6EwLs--



Roads with suffix in their number (e.g. N123a): use your brains. Almost 
every case is unique here so it's impossible to writ down a good rule.
e.g. N1c http://osm.org/go/0EpMnUUZ--
N60b http://osm.org/go/0EiFrVaz--
N15a http://osm.org/go/0EpLMAqA-
N42c http://osm.org/go/0EiwSJL_-


If a N-road really shouldn't be secondary at all, it can be classified 
unclassief/residential (not tertiary, if it can be tertiary it's sufficient to 
be secondary)
e.g. N408 http://osm.org/go/0EpSSDeg



(*) note that the previous years a lot of roads in city centers have been 
transferred from the region to the municipalities, and they lost their road 
numbers, so they've become tertiary even though there are probably still road 
numbers found on the street.



I guess these are the rules we have now. They sometimes allow for some 
discussion in some cases of course, but they do seem to create a nice map.

Ben