Triangles

[Chris Bertram]

Driving from work in Telford to Bromsgrove for a rehearsal last night, I decided not to attempt the M5, and took A442 and A448 via Bridgnorth and Kidderminster. While doing the latter part it occurred to me that A448, A449 and A450 form a triangle of consecutive road numbers, as A450 terminates on A449 south of Kiddy, and A448 crosses both the other two to the east of Kiddy. I tried later to think of other instances of this, and couldn't immediately come up with any. Are there any (surely there must be), and if so, where?

Incidentally, the above triangle didn't exist in 1922 as the route of A449 was different, going via Stourbridge and Bromsgrove, but I rather suspect that a triangle *did* exist anyway, as A450 then branched off A449 in Oldswinford, A449 terminated on A448 in Finstall and A450 and A448 crossed at Mustow Green, as today.

I'll get my coat, mine's the well-worn anorak in the corner.

[rileyrob]

The A901, 2 and 3 make a Triangle in Edinburgh, albeit with the tip chopped off. And I think that in 1922 the A92, 93 and 94 made a huge triangle across North East Scotland.

Not a Triangle, but the A857, 8 and 9 make a square on Lewis, and apart from the A91 getting in the way a little bit, the A912, 3 and 4 make a shape in Fife.

[DavidBrown]

I can go one better and give you a 'square' in Newton Abbot.
A380 along the east
A381 along the south
A382 along the west
A383 along the north.

[punyXpress]

A169 - A170 - A171 ?
Dangles from Whitby

[Chris Bertram]

A169 - A170 - A171 ?
Dangles from Whitby

Good one, I should have thought of that.

[punyXpress]

A173 & A174 extend that to a figure-of-eight but A172 spoils the plot with a dose of brewers droop!

[AndyB]

A20 Dundonald-Newtownards, A21 to Comber and A22 back.

A quadrilateral also exists in the same area, but it's a bit of a cheat because the consecutive numbers are on opposite sides:
A20 Belfast-Dundonald, A22 to Comber, A21 to Ballygowan, A23 to Belfast

Unfortunately we miss out on a pentagon - A3 Lisburn to Portadown, A4 to Ballygawley, A5 to Derry, A6 to Belfast is grand, but you have to take the pesky A1 to wreck things going back to Lisburn. The A2 meets the A1, A5, A6 and A8, but not the A3, A4 or A7.

EDIT: or you could take them out of sequence:

A3 Lisburn to Portadown, A4 to Ballygawley, A5 to Derry, A2 to Belfast, and A1 to Lisburn.

[rileyrob]

There is also the A75, 76 and 77 in south west Scotland. And you could argue that the A70, 71 and 72 (whilst multiplexing with the A73) works too.

Edit: and whilst we're in that area, the A77, 78 and 79 form a strange triangle too, and I think the A72, 73 and 74 used to work before the motorway took over.

[Chris5156]

A212, A213 and A214 form a triangle around South Norwood. A213, A214 and A215 also form a triangle, but the A212 passes through the middle of it.

[Bfivethousand]

Prior to the motorway age, the A45, A46 and A47 would have formed a triangle with Birmingham, Coventry and Leicester city centres being the three corners.

[Fenlander]

A15, A16, A17 used to but since the A16 was moved from Stamford to Peterborough it comes a few hundred yards short of meeting the A15.

[6637]

A3054, A3055, and A3056 almost manage to make a triangle, but not quite.

A590, A591, A592 is a triangle in Cumbria, as is A594, A595, A596.

[A9NWIL]

I have a sort of one with motorways involved, the A417/A419 as one side, M5 and M4 as the other two sides. Gloucester, Swindon and Bristol form the corners.

There is a motorway one south east of London with M26, M20 and M25, although you couldnt easily go round the triangle without using other roads.

Other motorway triangles include M8, M80 and M73 again its hard to do the whole triangle without using other roads. The M80, M876 and M9 make one too.
The M6, M61 and M62(including parts of the M60 that was originally M62) make a sort of strange shape one too.
Also the M1, A1(M) and M62 make one thats an odd shape too, as does the M1, M18 and M62.
Oh yes the M69, M6 and M1, but again you need to use other roads to get round the whole thing.
In the same area, A426, A428, and A5.

If you look at maps you can keep finding them all day long!

[Steven]

None of those are consecutive numbers, which is what was asked for.

[A9NWIL]

None of those are consecutive numbers, which is what was asked for.

Oh right sorry don't know why I missed that.

[wrinkly]

If the A74 had been numbered as A6, it would have formed a triangle with the A7 and A8!

[ScottB5411]

A583/4/5/6/7 form all sorts of shapes on the Fylde coast

[ScottB5411]

If the A74 had been numbered as A6, it would have formed a triangle with the A7 and A8!

Excellent!

[Chris Bertram]

If the A74 had been numbered as A6, it would have formed a triangle with the A7 and A8!

Yes, and if my auntie had ...

[Chris Bertram]

A583/4/5/6/7 form all sorts of shapes on the Fylde coast

There are some close groupings like this - and I'll bet there are some lurking within the North/South Circular roads - but just as often they're broken up, possibly because of a renumbering somewhere. A41/A42/A43 would, I think, have been an original example, until A42 got incorporated into A34.