Tightest Curve on a Motorway?

The study of British and Irish roads - their construction, numbering, history, mapping, past and future official roads proposals and general roads musings.

There is a separate forum for Street Furniture (traffic lights, street lights, road signs etc).

Registered users get access to other forums including discussions about other forms of transport, driving, fantasy roads and wishlists, and roads quizzes.

Moderator: Site Management Team

User avatar
trickstat
Member
Posts: 8738
Joined: Sun Apr 06, 2014 14:06
Location: Letchworth Gdn City, Herts

Re: Tightest Curve on a Motorway?

Post by trickstat »

JonB2028 wrote: Tue Dec 21, 2021 17:38
Unbreakify wrote: Tue Dec 21, 2021 14:25 The M90 is the tightest bend you'll get on a proper motorway, not a slip road.
The radius of the M90 bend looks to be around 500m. That figures as 510m is one of the tabulated radii in the DMRB - two steps below desirable minimum in current terminology and which used to be termed "limiting" in TD 9/81. I think what pre-dated this was similar, Road note ??

M69 approaching M1 J21 looks to be similar radius as does M11 in Woodford and M5 in West Bromwich. The M90 does look worse, being nearly 180 degrees, though.
The speed limit on the M11 heading north out of London goes up from 50 to 70 on a curve that makes 70 feel too fast (in my car at least).
Micro The Maniac
Member
Posts: 1175
Joined: Thu Jun 25, 2015 13:14
Location: Gone

Re: Tightest Curve on a Motorway?

Post by Micro The Maniac »

For mainline and not approaching terminal junctions, what about the M53(N) just after J5

Yes, I know it was meant to be different, but it's still a 90 degree bend at full motorway speed
User avatar
A42_Sparks
Member
Posts: 958
Joined: Mon Nov 17, 2003 23:20
Location: Ballymena, N Ireland

Re: Tightest Curve on a Motorway?

Post by A42_Sparks »

swissferry wrote: Mon Dec 20, 2021 18:57 Reminds me of M8 junction 15.
The loop at M8 junction 17 is even tighter.
Scratchwood
Member
Posts: 515
Joined: Tue Jul 08, 2008 21:44
Location: London

Re: Tightest Curve on a Motorway?

Post by Scratchwood »

drm567 wrote: Tue Dec 21, 2021 11:22 I nominate the off-slips at M1 jn. 6. https://www.google.co.uk/maps/@51.70494 ... 814635,16z The southbound one is particularly daft https://www.google.co.uk/maps/@51.70485 ... 384!8i8192 , look at the tyre marks left by vehicles that have been caught out. To compound the horror just round the bend is a 30 limit and two junctions with residential roads. (It's featured in Chris's site at https://www.roads.org.uk/badjunctions/1-405
https://www.google.co.uk/maps/@51.70689 ... 384!8i8192
https://www.google.co.uk/maps/@51.70485 ... 384!8i8192

What makes this extra dangerous, is that if any traffic comes off the Motorway too fast, they won't plough into a crash barrier, they'll plough into traffic going the other way, as the sliproads are basically S2!
kiran_mk2
Member
Posts: 83
Joined: Mon Nov 05, 2018 19:58

Re: Tightest Curve on a Motorway?

Post by kiran_mk2 »

Technically not a motorway (but it was supposed to an Expressway / A(M) road), but the A14 eastbound at Girton has a very sharp bend after you diverge from the M11.

https://www.google.com/maps/@52.2340367,0.0665423,15z

The road is now 2 lanes and there is a national speed limit sign literally on the bend (marking an end to VSL)
https://www.google.com/maps/@52.2321473 ... 384!8i8192

The road has alway been NSL even before the upgrade, but what is odd is that going westbound, there is a less tight (but longer) bend which was given a 50 mph limit when it was opened so I'm very surprised the eastbound one wasn't updated at the same time.
https://www.google.com/maps/@52.2303745 ... 384!8i8192

The eastbound bend can be taken at 70 mph but a lot of cars hit the breaks as the drivers realise how tight the corner is.
LoopyUpholland
Banned
Posts: 65
Joined: Wed Jul 21, 2021 17:11

Re: Tightest Curve on a Motorway?

Post by LoopyUpholland »

How tight was the old Strensham loop?
User avatar
Chris5156
Deputy Treasurer
Posts: 16908
Joined: Thu Sep 06, 2001 21:50
Location: Hampshire
Contact:

Re: Tightest Curve on a Motorway?

Post by Chris5156 »

LoopyUpholland wrote: Wed Jan 05, 2022 18:38How tight was the old Strensham loop?
A bit of measuring on Google Maps suggests it probably had a diameter of about 120-130m, which is about three times the size of M8 J17.

But of course the M8 loop is approached through a 30mph speed limit while the Strensham one was at the end of a lengthy straight where there was literally no speed limit!
Rambo
Member
Posts: 1056
Joined: Wed Dec 04, 2019 19:56
Contact:

Re: Tightest Curve on a Motorway?

Post by Rambo »

Nearly all of the examples i've seen are junctions, slip roads or spurs etc. For an actual mainline, this has to be a good contender https://www.google.com/maps/place/M53/@ ... -2.9826689
User avatar
JohnnyMo
Member
Posts: 6982
Joined: Wed Jun 04, 2003 13:56
Location: Letchworth, Herts, England

Re: Tightest Curve on a Motorway?

Post by JohnnyMo »

OK this is Germany A571 but tight for a mainline even if somewhat pointless motorway.
“The simple step of a courageous individual is not to take part in the lie" - Aleksandr I. Solzhenitsyn
Johnny Mo
kiran_mk2
Member
Posts: 83
Joined: Mon Nov 05, 2018 19:58

Re: Tightest Curve on a Motorway?

Post by kiran_mk2 »

If we're opening up foreign lands then the Innerbelt Curve on the I-90 in Cleveland is a corner I've driven. Marked down to a 35 mph limit and apparently known locally as Dead Man's Curve.

https://www.google.com/maps/@41.5165134 ... 384!8i8192

https://www.google.com/maps/place/Cleve ... 81.6943605
User avatar
Bryn666
Elected Committee Member
Posts: 35755
Joined: Thu Jun 20, 2002 20:54
Contact:

Re: Tightest Curve on a Motorway?

Post by Bryn666 »

kiran_mk2 wrote: Thu Jan 06, 2022 13:06 If we're opening up foreign lands then the Innerbelt Curve on the I-90 in Cleveland is a corner I've driven. Marked down to a 35 mph limit and apparently known locally as Dead Man's Curve.

https://www.google.com/maps/@41.5165134 ... 384!8i8192

https://www.google.com/maps/place/Cleve ... 81.6943605
They're gone now but the original S curve on the Lake Shore Drive in Chicago were literal 90 degree bends with, I think, 15mph speed limits.
Bryn
Terminally cynical, unimpressed, and nearly Middle Age already.
She said life was like a motorway; dull, grey, and long.

Blog - https://showmeasign.online/
X - https://twitter.com/ShowMeASignBryn
YouTube - https://www.youtube.com/@BrynBuck
FtoE
Member
Posts: 156
Joined: Sat Nov 30, 2013 09:43

Re: Tightest Curve on a Motorway?

Post by FtoE »

https://goo.gl/maps/jNBoMjuqZnSorC1S8

Westbound on the M8 just after the Kingston Bridge. There’s a fair old camber on it which helps.
RossNicol
Member
Posts: 46
Joined: Sun Mar 20, 2005 14:50
Location: Stirling

Re: Tightest Curve on a Motorway?

Post by RossNicol »

The M876 Westbound where it starts multiplexing with the M9 is quite tight

https://goo.gl/maps/5Yx9zzScurHknF7x8
User avatar
Barkstar
Member
Posts: 2603
Joined: Sun Jul 14, 2013 16:32

Re: Tightest Curve on a Motorway?

Post by Barkstar »

The M60 at Bredbury, as mentioned previously, does tighten a little, which is not ideal on a motorway. The M56 Sharston bypass, between Jct 3 and 2, is deceptive, with two apex and neither is a steady radius, both tightening. My own vote for off the mainline are the on and off slips for Jct 4 of the M621. At least they are steady radii :D
User avatar
Glen
Social Media Admin
Posts: 5426
Joined: Mon Mar 13, 2006 02:16
Location: Inbhir Pheofharain
Contact:

Re: Tightest Curve on a Motorway?

Post by Glen »

A42_Sparks wrote: Thu Dec 23, 2021 18:53 The loop at M8 junction 17 is even tighter.
Although, despite the erroneous placement of the signs, the loop isn't on the motorway and is a sliproad between the A82 and the A804.
swissferry
Member
Posts: 319
Joined: Tue Aug 22, 2017 20:42

Re: Tightest Curve on a Motorway?

Post by swissferry »

Glen wrote: Sun Jan 09, 2022 19:08
A42_Sparks wrote: Thu Dec 23, 2021 18:53 The loop at M8 junction 17 is even tighter.
Although, despite the erroneous placement of the signs, the loop isn't on the motorway and is a sliproad between the A82 and the A804.
Never realised it wasn't motorway but it makes sense that it isn't. OSM has the loop as motorway between A82 and A804 making it a contender for shortest motorway! OS has it as an A road.

Was discussed previously in the Motorway Abnormalities thread where a post says the signs on the loops were incorrect and would be removed in the near future - back in 2003.
David D Miller wrote: Thu Apr 17, 2003 09:24 Feedback from Amey Highways regarding the signing from the A82 and A804 at the M8 J17 westbound entry:
The westbound link road from the A804 to Charing Cross is not motorway, and is correctly signed. The loop from the eastbound A82 to the link road from the A804 is not motorway, and the two signs on it indicating start of M8 are both wrong. These two signs are already scheduled to be removed in the near future.
Duncan macknight
Committee Member
Posts: 338
Joined: Thu Jul 23, 2015 10:59
Location: Inverness

Re: Tightest Curve on a Motorway?

Post by Duncan macknight »

JonB2028 wrote: Tue Dec 21, 2021 17:38
Unbreakify wrote: Tue Dec 21, 2021 14:25 The M90 is the tightest bend you'll get on a proper motorway, not a slip road.
The radius of the M90 bend looks to be around 500m. That figures as 510m is one of the tabulated radii in the DMRB - two steps below desirable minimum in current terminology and which used to be termed "limiting" in TD 9/81. I think what pre-dated this was similar, Road note ??
The Radius of the bend is 694m, as is the curve the M90 has passing under J10 Craigend!
User avatar
A42_Sparks
Member
Posts: 958
Joined: Mon Nov 17, 2003 23:20
Location: Ballymena, N Ireland

Re: Tightest Curve on a Motorway?

Post by A42_Sparks »

Glen wrote: Sun Jan 09, 2022 19:08
A42_Sparks wrote: Thu Dec 23, 2021 18:53 The loop at M8 junction 17 is even tighter.
Although, despite the erroneous placement of the signs, the loop isn't on the motorway and is a sliproad between the A82 and the A804.
Thanks I wasn't even sure myself, that junction has a very unusual design.
paully
Member
Posts: 1196
Joined: Wed Sep 07, 2005 11:48
Location: Perth

Re: Tightest Curve on a Motorway?

Post by paully »

Duncan macknight wrote: Mon Jan 10, 2022 10:34
JonB2028 wrote: Tue Dec 21, 2021 17:38
Unbreakify wrote: Tue Dec 21, 2021 14:25 The M90 is the tightest bend you'll get on a proper motorway, not a slip road.
The radius of the M90 bend looks to be around 500m. That figures as 510m is one of the tabulated radii in the DMRB - two steps below desirable minimum in current terminology and which used to be termed "limiting" in TD 9/81. I think what pre-dated this was similar, Road note ??
The Radius of the bend is 694m, as is the curve the M90 has passing under J10 Craigend!
The curve on the M80 as it goes under the railway bridge here (https://goo.gl/maps/FCP2yHRviV8kC5av7) is much tighter, albeit it's subject to a 50mph limit. I reckon the radius is as tight as 250m on the Southbound carriageway.
paully
Member
Posts: 1196
Joined: Wed Sep 07, 2005 11:48
Location: Perth

Re: Tightest Curve on a Motorway?

Post by paully »

FtoE wrote: Mon Dec 20, 2021 22:31
DB124 wrote: Mon Dec 20, 2021 18:17 Not very original, I know.
But, this question comes in two parts:
-Which is the tightest curve on the mainline of a motorway?
-and which is the tightest curve under motorway restrictions?

For the former, my intuition tells me M90 Balmanno Hill or Queensferry, though it is possible that an urban motorway has a sharper curve (A167(M), M4). I haven't included Simister or Worsley because neither were designed as a mainline motorway.

For the latter, a more interesting task is presented. For example, this one west of Newport seems ludicrous. And whoever thought two lanes was a safe idea at Tebay needs to be fired. Is there a cloverleaf loop tighter than these? Or perhaps a really nasty roundabout approach with some awkward corners?

Would love to hear everyone's thoughts and insights on corners with Blue Signs. :)
The M90 southbound at Craigend (J10) was until a few years ago a tight two-lane

https://goo.gl/maps/wHhW4sfoezwV5uXb8
That sliproad has been a single lane for as long as I can remember, certainly for the last 30 years. The second lane used to end about where that streetview photo was taken, prior to the current layout where the sliproad is a lane drop. The sliproad from the Friarton Bridge towards the Broxden spur (https://goo.gl/maps/wibmwCtzvUoGj6B79) had 2 lanes until about 10 years ago - are you thinking of this instead?
Post Reply