[OSM-talk] [OSM-newbies] Trunk and primary roads in Britain

David Ebling dave_ebling at yahoo.co.uk
Tue Dec 30 12:48:56 GMT 2008


I don't believe that all A roads will be re-signed with green signs. There is still a distinction between (former) trunk roads and other A-roads. Green signed roads are generally more important roads, and usually built to a better standard. 

I think the current OSM situation is far more sensible than tagging roads according to who maintains them, which is far harder to ascertain, and of little interest to people reading maps.

Most other maps I've seen are similar to OSM (eg http://www.streetmap.co.uk/idl.srf?X=301500&Y=525500&A=Y&Z=120&lm=1 for OS) or have a totally arbitrary mix of colours for green-signed roads, which often make no sense. (eg http://www.multimap.com/s/B2JuJ4Qw)

cf OSM: http://www.openstreetmap.org/?lat=54.6127&lon=-3.5277&zoom=14&layers=0B00FTF



--- On Tue, 30/12/08, Mike Harris <mikh43 at googlemail.com> wrote:

> From: Mike Harris <mikh43 at googlemail.com>
> Subject: [OSM-newbies] Trunk and primary roads in Britain
> To: newbies at openstreetmap.org
> Date: Tuesday, 30 December, 2008, 9:10 AM
> Advice please for a relative newbie.
> Until the mid-1990s, trunk roads in Britain were managed by
> a central government agency (in England, the Highways
> Agency) and other roads, including other primary roads, were
> managed by local authorities. All primary roads were
> numbered "Annnn" (n - up to 4 digits) - many maps
> (including the Ordnance Survey) further distinguished trunk
> roads by adding a descriptor thus "Annnn (T)". OSM
> largely, but not entirely, reflects this historical
> situation with the separate tags highway:trunk and
> highway:primary being differently rendered (e.g. green for
> trunk and red for primary in Osmarender).
> The comment for trunk roads on the map features main page
> of the OSM Wiki reads:
> "Important roads that aren't motorways. Typically
> maintained by central, not local government. Need not
> necessarily be a divided highway. In the UK, all green
> signed A roads are, in OSM, classed as
> 'trunk'."
> and for primary roads:
> "Administrative classification in the UK, generally
> linking larger towns."
> Unfortunately, in the mid-1990s nearly all trunk roads in
> Britain were "de-trunked" and their maintenance
> transferred from central to local government (in England,
> for example, the Highways Agency). There are now very few
> trunk roads in the country - see map at
> http://www.highways.gov.uk/aboutus/6151.htm . This change is
> reflected in most recent mapping (including the OS - note
> how the "(T)" suffix has disappeared from almost
> all A roads that formerly had it) - except OSM!
> If we take the current legal situation at face value, we
> should logically change in OSM most of the roads tagged as
> "trunk" to "primary" - and this would
> best be done wholesale rather than piecemeal (if this is
> possible).
> The current comments on the map features page are now at
> best confusing and perhaps incorrect. All A roads are green
> signed (or will be as older white signs are replaced) but
> almost all are maintained by local government - so the
> comment on trunk roads is now self-contradictory. AFAIK
> there is no administrative classification for primary roads
> other than as "A" roads - so the comment on
> primary road also contradicts the comment on trunk roads.
> Being a logical sort of person and wanting OSM to be
> up-to-date, I am tempted to change the advice in the Wiki
> and to change "trunk" to "primary" as I
> come across them via my GPX traces - but I don't want to
> act unilaterally.
> May I recommend strongly that we bring OSM up-to-date with
> the current administrative situation in Great Britain and
> reclassify trunk roads as primary wherever they have been
> detrunked? Is there a generic way of doing this centrally?
> (I am nowadays "only" a mapper and no longer a
> coder).
> mikh43
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