[OSM-talk] Red and green routes

[Richard Fairhurst]

On 21 Nov 2006, at 00:19, David Earl wrote:

>> Most UK maps would paint the primary routes green, and the secondary
>> ones red - not least because primary routes over here have green
>> signs.
>
> No they wouldn't. OS and most atlases have TRUNK in green, PRIMARY  
> in red (A
> roads which aren't trunk roads) and SECONDARY in yellow/orange (B  
> roads).
> Tertiary are white (unnumbered on OS maps but local authorities have C
> numbers for most of them).

One or other of us is confused about terminology and naturally I  
don't think it's me. ;)

Trunk roads (which are now called 'strategic roads') are a small  
subset of the UK road network. They used to be marked on OS maps by  
the addition of '(T)' to the road number. Andy has observed they used  
to be all the two-digit roads. Nowadays the trunk/strategic road  
network is much smaller; you can see it at http://www.highways.gov.uk/ 
aboutus/documents/inside_front.pdf

For example, a primary, two-digit road like the A41 from the M40  
(Bicester) to the M25 (King's Langley) is not a trunk/strategic road  
- although it's signed in green, and marked in green on OS  
Landranger, Collins/Bartholomew raster, maps.google.co.uk, and the AA  
road atlas. (OS Explorer, and I suspect Streetview, used to mark  
_all_ A roads as red, including trunk, but have now switched to green.)

Primary routes are those A roads which are signed in green, including  
trunk routes. These are marked in green on most maps. See http:// 
www.highwaycode.gov.uk/signs06.htm for citation.

'Secondary' A-roads are those which are signed in black/white. These  
are marked in red on most maps. FWIW I believe these are strictly  
called non-primary, but secondary follows logically on from primary  
and seems a logical shorthand.

For B-roads and minor/unclassified we agree on the colouring.

cheers
Richard

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