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

Tom Hughes tom at compton.nu
Thu Jan 1 14:45:53 GMT 2009

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)

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