A418 at Thame (Primary or Non Primary)

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A418 at Thame (Primary or Non Primary)

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Can anyone tell me if the section of the A418 from the A40 at Wheatley (east of Oxford) to Aylesbury (by-passing Thame) is a Primary Route. Half of my maps and atlases (the AA and Collins) show the road as a Primary Route (coloured green) and others (OS and A-Z) show it as a Non Primary Route (coloured red). The road has green Primary Route signs along the whole of this section so if I was to have a guess I would say that the road is a Primary Route but I still can't be sure. Interestingly on the SABRE Wiki it has the road key showing it as Non Primary but the map shows it as Primary.
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Re: A418 at Thame (Primary or Non Primary)

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Typically the little maps are sourced from OSM trace data.

I don't know the answer to the question though.
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KeithW
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Re: A418 at Thame (Primary or Non Primary)

Post by KeithW »

I may well be wrong but it is my understanding that to be a Primary Route you had to have one or more continuous A roads linking two Primary Destinations. As the A418 runs from Leighton Buzzard to Wheatley neither of which are primary destinations I dont see how it could be primary. Aylesbury is a PD but I cannot think of any others on the route.

That said historically the A418 continued to Bedford so the Aylesbury to Bedford section probably would have been considered Primary but that was lost with the improvements to the A421 and was downgraded and renumbered
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Chris Bertram
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Re: A418 at Thame (Primary or Non Primary)

Post by Chris Bertram »

KeithW wrote: Mon Sep 24, 2018 15:21 I may well be wrong but it is my understanding that to be a Primary Route you had to have one or more continuous A roads linking two Primary Destinations. As the A418 runs from Leighton Buzzard to Wheatley neither of which are primary destinations I dont see how it could be primary. Aylesbury is a PD but I cannot think of any others on the route.

That said historically the A418 continued to Bedford so the Aylesbury to Bedford section probably would have been considered Primary but that was lost with the improvements to the A421 and was downgraded and renumbered
A418 is there to connect Oxford with Aylesbury, but doesn't get all the way to Oxford because A40 completes the job. I'd say that's good enough for green signs.
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KeithW
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Re: A418 at Thame (Primary or Non Primary)

Post by KeithW »

Chris Bertram wrote: Mon Sep 24, 2018 15:49
A418 is there to connect Oxford with Aylesbury, but doesn't get all the way to Oxford because A40 completes the job. I'd say that's good enough for green signs.
[/quote]

Sounds reasonable to me.
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Re: A418 at Thame (Primary or Non Primary)

Post by Robert Kilcoyne »

KeithW wrote: Mon Sep 24, 2018 15:21 I may well be wrong but it is my understanding that to be a Primary Route you had to have one or more continuous A roads linking two Primary Destinations. As the A418 runs from Leighton Buzzard to Wheatley neither of which are primary destinations I dont see how it could be primary. Aylesbury is a PD but I cannot think of any others on the route.

That said historically the A418 continued to Bedford so the Aylesbury to Bedford section probably would have been considered Primary but that was lost with the improvements to the A421 and was downgraded and renumbered
The A418 is primary east of Aylesbury (according to the OS maps) as far as the Leighton Buzzard bypass, where it terminates now. Although Leighton Buzzard is not a primary destination itself, the A418 can be viewed, together with the A505, rerouted A5, M1 and A505 again as the main route between Aylesbury and Luton.
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Re: A418 at Thame (Primary or Non Primary)

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The A418 at Thame is now shown as a Primary Route on all scales of OS mapping. A-Z and AA road atlases now also show this section of the A418 as a Primary Route (they had previously shown it as Non Primary) so it looks like it has changed in recent years. The only thing that I can't understand is the way it's shown on the Collins Road Atlas of Great Britain. The section in Oxfordshire is shown as Non Primary (coloured red) but it appears to change to a Primary Route at the county border at Thame and the section of the road within Buckinghamshire is shown as Primary (coloured green). I would say that this must be a mapping error as all signage along this whole section of the A418 is Primary. Also the route outline key on the Wiki still has this section of the A418 as Non Primary which is incorrect. I've had a look but can't seem to be able to change it.
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Re: A418 at Thame (Primary or Non Primary)

Post by c2R »

roadphotos wrote: Mon Nov 01, 2021 19:26 The A418 at Thame is now shown as a Primary Route on all scales of OS mapping. A-Z and AA road atlases now also show this section of the A418 as a Primary Route (they had previously shown it as Non Primary) so it looks like it has changed in recent years. The only thing that I can't understand is the way it's shown on the Collins Road Atlas of Great Britain. The section in Oxfordshire is shown as Non Primary (coloured red) but it appears to change to a Primary Route at the county border at Thame and the section of the road within Buckinghamshire is shown as Primary (coloured green). I would say that this must be a mapping error as all signage along this whole section of the A418 is Primary. Also the route outline key on the Wiki still has this section of the A418 as Non Primary which is incorrect. I've had a look but can't seem to be able to change it.
I've changed it - were you getting any sort of error that was preventing you from doing it?
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Re: A418 at Thame (Primary or Non Primary)

Post by roadphotos »

Thanks for changing it. I must have been looking at the wrong place, I clicked on edit but I couldn't see the map key.
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