[OSM-talk] definition of the main highway-tag

[Christiaan Welvaart]

On Sat, 1 Aug 2009, Martin Koppenhoefer wrote:

> 2009/8/1 Christiaan Welvaart <cjw at daneel.dyndns.org>:
>> On Fri, 31 Jul 2009, Martin Koppenhoefer wrote:
>> Why would who maintains a road directly determine its administrative
>> classification? If a municipality decides that some road is a motorway, we
>> better tag it as such. In The Netherlands some provinces maintain short
>> stretches of motorway, for example, while most motorways are maintained by
>> the national government. The maintainer of a road can be tagged
>> independently. So is it really a big change for Germany and Italy to define
>> the highway tag as the administrative classification of the road?
>
> seems as if you got me completely wrong. The administrative
> classification _IS_ about who maintains the road (at least in Germany
> and Italy). While BAB (Bundesautobahn / motorway) and Bundestraße
> (federal road) are maintained by the federal administration,
> Landstraßen (~"Land"-roads) are maintained by the Bundesland (~region)
> and Kreisstraßen (comunal road) by the municipality. But as I tried to
> explain this does not mean that every Bundesstraße is a bigger and
> more important road. There are Kreisstraßen (comunal roads) that are
> more important (and physically bigger) than other Bundesstraßen or
> Landstraßen. That's why we cancelled the idea of tagging highway
> according to administrative class already years ago. Of course I don't
> want to reimplement it.

It seems to be an interpretation problem for the phrase 'administrave 
class' then because I clearly argued that who is the maintainer of the 
road should not directly influence the value of the highway tag. What I 
was trying to say is that I'd prefer to tag the importance that the road 
maintainer sets for a road. This *class* can usually be derived from how 
it was built, the maximum speed on the road, etc., not from how many cars 
actually drive on it or even its position in the grid. Road maintainers 
also take other things into account like how many houses are near the 
road, how much pollution and noise will be generated by traffic on the 
road, etc.

On the other hand a road's class is often not clearly visible except for 
motorways. Also, there is usually no uniform classification system 
available - there is a proposed system for The Netherlands but it only has 
3 categories which is not really enough...

So in the context of Germany I say take 'Autobahn' and 'Kraftfahrstrasse' 
as a classes for the highway tag (not 'Bundesstrasse' and 
'Landesstrasse'). These terms are defined in law, so it is not something 
OSM invented or a vague importance of the road.

>> The problem with 'importance' is that it is too vague and it is the task of
>> the road maintainer to determine/define a road's function. Also, if there is
>> a mismatch between a road's classification and its 'importance',
>> we should tag the classification.
> what do you mean by classification? Administrative, physical or
> importance? There is clearly all the three of them, and of course I
> want to tag the administrative classification (inside ref-tag) but not
> as the parameter for the highway-class.

I mean how the road maintainer designates the road.

>> An example is a route through a town
>> to a motorway access. The municipality this town belongs to considers this
>> route inappropriate, while the municipality where the route starts considers
>> it an appropriate route. The road inside the town is still tagged as
>> secondary, while its maxspeed was already lowered to 30km/h. AFAIK its
>> 'importance' has not changed, however, as no alternative route to this
>> motorway access is available (there are several alternative access points to
>> this an other motorways, though). So, do you think we should keep it as
>> secondary which probably matches its importance (access to a motorway)
>
> yes, of course. Because as you wrote: there is no other way, i.e. if
> you want to go to this motorway, you will have to take it -> it is
> important, gets a high class (secondary or primary).

No, I said there are other routes. This is just the shortest or fastest 
route for some people I guess.

>> or
>> tag it as tertiary or even lower which matches its classification (only
>> meant for traffic from and to the town)?
> of course not.

Well I disagree. IMHO we should tag what is 'on the ground', not invent 
things or try to tag what's in people's minds. If a government body gives 
a road it maintains some importance (or class/type) we should tag it 
accordingly.

Another example is Bicycle streets. These are designated by municipalities 
in .nl (and .de) but they do not have a uniform importance: for cars they 
are e.g. a living street but for bicycles they are part of an important 
and much used route. These roads are classified specially by the road 
maintainer, and this should be reflected in the highway= value. What is 
the conclusion according to your proposal?

Anyway how do you determine if something is a cycleway, from its 
importance and its position in the grid? That does not work while it would 
be nice to have a uniform definition for the highway key.


     Christiaan