Talk:WikiProject Belgium/Conventions/Highways
Changing the rule for N-roads within the Brussels-Capital Region
I suggest mentioning the classification rule for N-roads does not apply within the Brussels-Capital Region.
According to the current revision of the page, N-roads of the 1st and 2nd category are expected to be tagged as highway=primary.
The mobility plan of Brussels-Capital Region, named Good Move, aims to change motor traffic flows within the city. The Region’s current vision is highway specialisation (FR: "spécialisation multimodale des voiries", NL: "multimodale wegenspecialisatie") which divides roads into 3 categories: main (Auto plus), intermediate (Auto confort/comfort) and local (Auto quartier/wijk). The main idea is to reduce traffic on local and intermediate roads and concentrate traffic on the main roads.
Many N-roads in Brussels are narrow urban roads, and they belong to the intermediate or local category. Since 2021, many of them apply a 30-kph speed regime. The implementation of the highway specialisation scheme started in mid-2022 in some neighbourhoods and is expected to continue until around 2030. As a consequence, the effective road structure in Brussels already significantly differs from the classification that would primarily rely on the historical ref number of such roads. It is desirable that OSM reflects the real traffic hierarchy, hence the need to add an exception to the rule in the table. Bxl-forever (talk) 16:25, 14 January 2023 (UTC)
Refining the conventions for road classification
Because I've noticed that some mappers use the current conventions too strictly, I propose these changes which reflect more the current mapping practices:
Primary
Usually national roads, N-roads of the 1st and 2nd category that usually connect the capitals of the provinces with ref= Nx (1 to 9)or Nxx (tens from 10 to 90). Or any other road or ring road (with ref=Rx or Rxx) that has taken over the function of these roads.
Secondary
Usually the other National roads, N-roads of the 3th and 4th category, with ref=Nxx or Nxxx with digits only (no character), if they function as a road connecting large towns/cities. Or any other road connecting large towns/cities.
Tertiary
All other connecting roads between villages or residential areas.
Notes:
The distinction between trunk and primary is very unclear. Some guidelines:
- A motorroad (F9) is usually a trunk road, but not always. E.g. the tunnel of the Antwerpsesteenweg underneath the railway in Lier has a F9 sign but is a tertiary road.
- A road which has the look and feel of a motorway (with sliproads and often a speed limit of 90 or 120 km/h) is a trunk road (e.g. most of the N4 between Namur and Arlon).
- A road with C9/C11/C19 traffic signs is usually a trunk road.
- A ringway or any road which has a limited amount of crossroads and diverts traffic around cities and villages or is a direct link between a motorway and a neighboring city is more likely to be a trunk road, and even more of it is a 2x2 road.
- A road not connected to any other motorway, trunk of primary road is probably not a trunk road.
Be aware that a trunk road has default access restrictions (https://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Access_restrictions#Belgium), so adjust them with access tags if necessary.
Any former primary road that has lost its function should be mapped accordingly as secondary, tertiary or even residential/unclassified.
Any former secondary road that has lost its function (or never had the function as a road connecting large towns/cities should be mapped accordingly as tertiary or residential/unclassified. Any secondary road that has taken up or over the role as a road of the 1st and 2nd category, should be mapped accordingly as primary or even trunk.
Any former tertiary road that has taken up or over the role of a secondary or primary road should be mapped accordingly.
Nx/Nxxx roads with a supplemental 'downgrading' letter could be anything: often they are downgraded Nx/Nxxx roads (e.g. N72a through the center of Beringen), but sometimes they are new main roads (e.g. N19g between Geel and Kasterlee).