[Tagging] Classifying roads from Trunk to Tertiary and Unclassified

Philip Barnes phil at trigpoint.me.uk
Mon Aug 12 18:27:43 UTC 2019

On 12/08/2019 19:06, Paul Allen wrote:
> On Mon, 12 Aug 2019 at 18:25, Fernando Trebien 
> <fernando.trebien at gmail.com <mailto:fernando.trebien at gmail.com>> wrote:
>     There are all sorts of opinions on this matter, but trying to define
>     classification rules based on physical characteristics or
>     administrative responsibility (municipality, state or national) always
>     led to unexpected situations here. I guess the UK is somewhat unique
>     in having an official classification system that matches the
>     topological organization of the road system.
> I would hope the UK is not unique.  The reason it matches (mostly) in 
> the UK is that
> the classification was assigned based on the characteristics of the 
> roads.  It
> wasn't somebody making decisions based upon a whim, it tried to assign
> categories based upon usage: it defined a route as being primary if it was
> the best route.
The UK is not unique. When I first drove to Paris back in 1981, I went 
on the hovercraft to Boulogne and then drove down the N1 to Paris.

It was much like a UK trunk road, mostly two lane, streches of dual 
carriageway and it passed through villages and towns along the way. Far 
nicer than boring Motorways.

I used that route many times over the years, however France 
deccentralised its network and much of this has been lost.

In England/Wales, the road network radiates out from London, with the 
single A digit roads leading to the major destinations.

A1 to Edinburgh, A2 to Dover, A3 to Portsmouth, A4 to Bath, A5 to 
Holyhead and A6 to Carlilse. The network is divided into zones, hence 
most A and B roads between the A5 and A6 (my zone), with start with a 5. 
The exceptions will be roads which  start in a different zone.

Scotland has a similar systen radiating from Edinburgh.

The term trunk is based on the trunk of a tree, with other roads 
branching off.

Phil (trigpoint)

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