[OSM-newbies] Trunk and primary roads in Britain

[Mike Harris]

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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