[OSM-talk-be] Highway classification in Brussels region

[Ben Laenen]

On Tuesday 05 June 2012 17:49:40 Benoit Leseul wrote:
> Hi all,
> 
> A few weeks ago, I was showing Brussels map to someone (OSM with
> Mapquest Open style), and they made the observation that it was absurd
> that Chaussée de Waterloo (N5) stood out as a major road while Avenue
> Brugmann/Rue de Stalle (N261) looked like a minor artery.
> 
> I understand this comes from
> http://wiki.openstreetmap.org/wiki/WikiProject_Belgium/Conventions/Highways
> which talks about historical Nx and Nxx classification.

A few quick points because I don't have a lot of time to write a full reply 
right now:

To start with: one problem with Brussels is that they don't use road numbers 
anymore over there, so there's not much of a classification left. So I'd say 
that within the boundaries of Brussels you have some freedom to choose between 
primary or secondary.

Also, the current primary/secondary distinction doesn't play out that well in 
some other situations in Belgium either. But we basically lack a better 
definition, and using Nxx vs Nxxx is "good enough". Note that other maps one 
would call professional, like those from the NGI/IGN use the same system.

Also, if you look at the classification as it's done in other countries in 
OSM, they also chose one based on road numbers. So, it's somewhat an 
"international convention" to use it.


Now, our governments do make classifications for each road, and I guess each 
one does it in its own way. Our Flemish government uses a system from main 
road (basically motorways), primary road I, primary road II, secondary I ... 
local III etc. That would give a good representation of what's on the road, 
but we don't have access to this classification so we can't use it.


In short: yeah, the system isn't optimal. But it's the best we can do for now. 
It's in line with other countries and uses objective criteria. Other options 
would soon provoke numerous discussions on what classification each road 
should have...


> (...)
> 
> So, I have two questions:
> - (a) do you think it is a good idea to take this map as a source (can
> we?) or "inspiration" to requalify most main roads in the Brussels
> region?
> - (b) if yes, how do we match the different road levels? My impression
> is that we should merge "voie métropolitaine" (red) and "voie
> principale" (orange) and use highway=primary for both, while keeping
> highway=secondary for "voie inter-quartiers" (blue) and
> highway=tertiary for "collecteurs principaux" (green).

If you use that map, then you need to have
- red -> primary
- orange -> secondary
- green and blue -> tertiary

That would be much closer to the OSM classification. Making all the blue ones 
secondary will just create a big sea of secondary roads... One could choose 
(and maybe it would be even better) to put all the roads managed by the 
Brussels-Capital Region that are green or blue on the map as secondary as 
well.

At least, that's my view on this :-)

Greetings
Ben