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

[Benoit Leseul]

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. But it
certainly doesn't match reality if you are driving in the city. Inside
Brussels, Chaussée de Waterloo is a narrow and overcrowded street
while Avenue Brugmann is a wide road with two reverse lanes and a
tramway reservation in the middle. It is actually a major axis to
enter and exit the city, connecting with R0 in Drogenbos.

What I dit then is to upgrade Brugmann/Stalle to "major road"
(highway=primary) as well as a few other similar connecting roads in
the vicinity (namely Churchill and Albert). I think it looks better,
but still doesn't reflect the reality of N5 being smaller.

Now someone pointed me today to the Brussels region "Iris 2" plan,
which has a nice map on p88 ("La spécialisation des voiries") showing
a completely different road classification :
http://www.bruxellesmobilite.irisnet.be/articles/la-mobilite-de-demain/en-quelques-mots
It may look like wishful thinking in some places and I can see a few
glitches here and there, but it is certainly more useful for someone
actually trying to find his way in the city. The only real problem I
have with it is that it has four levels of hierarchy when OSM only
provides three (primary, secondary, tertiary).

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).

What do you think?

-- 
Benoit