[OSM-talk] Trunk and primary routes in the UK

Mike Harris mikh43 at googlemail.com
Thu Jan 1 15:42:06 GMT 2009


I thought that I had backed off and cleared things up - sorry! Unfortunately your message - for me at least - adds further to the confusion. Surely in the UK "primary" roads (and trunk roads of course) are A roads and A roads are primary roads - whether or not they are part of the "primary route network" (as indicated by street sign colour). OSM has chosen to define its tagging and rendering according to the "primary route network" (and street sign colour) and I am no longer questioning this and have already apologised and corrected back the few changes I had made. BUT ... A roads with white signs are surely still primary roads (and should be tagged as such)? To call an A road a "secondary" road adds enormously to the potential confusion as the term "secondary" is surely reserved in legal, common and OSM parlance for B roads?

Please understand that having raised the issue as a question, having received a firm response from the "old hands" and having willingly accepted this advice as to how best to tag, my only concern is that I do still find the entry on the wiki main page extremely confusing. It certainly wouldn't help - IMHO - to start using a term "secondary A roads" - a real contradiction in terms. I can live with OSM using "trunk" to mean an A road with green signs that is part of the primary road network and using "primary" to mean any other A road (i.e. those with white signs and not forming part of the primary road network) and have willingly accepted this as part of my learning. I do think, however, that to start talking about "secondary A roads" is a real recipe for disaster and endless confusion. Can we not simply live with the terms "primary" and "trunk" as presently defined in OSM and reserve the expression "secondary" for B roads - AFAIK this is what is actually happening on OSM and is consistent with all of the mapping and rendering done so far?


-----Original Message-----
From: Tom Hughes [mailto:tom at compton.nu] 
Sent: 01 January 2009 14:46
To: Mike Harris
Cc: talk at openstreetmap.org
Subject: Re: [OSM-talk] Trunk and primary routes in the UK

Mike Harris wrote:

> I seem to have stirred up a bit of a hornet's nest by raising this 
> issue
> - for which I apologise. The key issue - I have now learnt from this 
> mailing list - seems to be the difference in the UK between the 
> "primary route network" (green signs, conventionally tagged in OSM as
> highway=trunk) and "primary routes" (all A roads - green or white 
> signs; green ones tagged highway=trunk, white ones tagged 
> highway=primary). I respect the established convention and will not 
> make any further changes (I assume all A roads in the UK have been 
> done by now?). AFAIK I have corrected back to the established 
> convention the very few changes that I have made. On the assumption 
> (:>) that I am not entirely unintelligent, I do still find the 
> instruction on the main map features page of the osm wiki very 
> confusing - that is what started this thread for me. Perhaps you, or 
> someone else long-established in the world of OSM, could consider editing the wiki to make it clearer?

The point is that the description you have given here is not, as far as we are aware, correct.

Our understanding is that only primary A roads (also known as the primary route network) have green signs and that secondary A roads have white signs. We use "trunk" for the former and "primary" for the latter as there are very few genuine trunk roads left and this distinction makes more sense as a result.


Tom Hughes (tom at compton.nu)

More information about the talk mailing list