Smallest and largest freeflow interchanges
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Smallest and largest freeflow interchanges
What are the most compact, or the most sprawling, interchanges you know of?
I'll start off with one contender for each from Qatar:
This one Google Maps OSM link manages free-flow turns and straight-across movements in all directions but has built-up areas right up close to it, and is only about 150m across.
Whereas the new Orbital Highway has some absolutely gargantuan interchanges such as this stack interchange Google Maps OSM link, which is about 600m across at its minimum.
I'll start off with one contender for each from Qatar:
This one Google Maps OSM link manages free-flow turns and straight-across movements in all directions but has built-up areas right up close to it, and is only about 150m across.
Whereas the new Orbital Highway has some absolutely gargantuan interchanges such as this stack interchange Google Maps OSM link, which is about 600m across at its minimum.
Re: Smallest and largest freeflow interchanges
Locally Croft Interchange is huge.
From the westbound exit slip road leaving, to the eastbound exit slip road leaving, the two extreme points of the interchange, is a distance of 2520m, or just over 1.5 miles.
You can fit the circle of the Coventry Ring Road between those two diverges twice.
From the westbound exit slip road leaving, to the eastbound exit slip road leaving, the two extreme points of the interchange, is a distance of 2520m, or just over 1.5 miles.
You can fit the circle of the Coventry Ring Road between those two diverges twice.
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Re: Smallest and largest freeflow interchanges
This would probably count technically as a free-flow interchange: https://www.google.co.uk/maps/place/070 ... d8.9400383
It won't be the world's largest, but it has always struck me as being 'unnecessarily large' (and confusing in the middle of the night, too!).
Italy seems to specialise in both extremes of 'sprawling interchanges' and 'unbelievably compact' ones.
It won't be the world's largest, but it has always struck me as being 'unnecessarily large' (and confusing in the middle of the night, too!).
Italy seems to specialise in both extremes of 'sprawling interchanges' and 'unbelievably compact' ones.
Re: Smallest and largest freeflow interchanges
The most compact freeflow GSJ will obviously be a very small cloverleaf at the junction of two single carriageways. Italy may well be a contender given the rather dodgy GSJ's I've seen over there.
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Re: Smallest and largest freeflow interchanges
How can this count as free flowingOwain wrote: ↑Thu Jul 09, 2020 18:46 This would probably count technically as a free-flow interchange: https://www.google.co.uk/maps/place/070 ... d8.9400383
...
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Re: Smallest and largest freeflow interchanges
It's in Italy.
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Re: Smallest and largest freeflow interchanges
It's also on Google Maps, which means it's a mistake! Should've referenced SABRE Maps instead!!
The thing is a massive anticlockwise gyratory which has no 'stop' or 'give way' signs/lines. In some places - possibly even all of it - the carriageway is a one-way S3. There is so little traffic that you can drive through it without meeting more than one or two other vehicles at any time of day or night. In fact the only reason for even slowing down at all is to avoid missing an exit and having to drive all the way round the thing again (I think my record was 3 laps before finding the correct turn, after discovering that the sign had fallen off its post!).
Re: Smallest and largest freeflow interchanges
There are roundabouts which are truly freeflowing with no stop or give way markings.
https://goo.gl/maps/zJLWKhfZrWfGPe7N7
https://goo.gl/maps/zJLWKhfZrWfGPe7N7
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Re: Smallest and largest freeflow interchanges
I remember last year there was a thread on Massive Junctions, and I compiled a list
viewtopic.php?f=1&t=40885&p=1086016#p1086016
The biggest definitive single one in the UK I could find was Croft, with an internal area of 90 hectares. The only bigger ones were the M6-M6(T)-M42 at Water Orton, which is really a set of linked junctions and the M3-M27 that may or may not be a single junction. However both of these have some ends that drop off to roundabouts, so probably don't qualify for this thread.
viewtopic.php?f=1&t=40885&p=1086016#p1086016
The biggest definitive single one in the UK I could find was Croft, with an internal area of 90 hectares. The only bigger ones were the M6-M6(T)-M42 at Water Orton, which is really a set of linked junctions and the M3-M27 that may or may not be a single junction. However both of these have some ends that drop off to roundabouts, so probably don't qualify for this thread.
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Re: Smallest and largest freeflow interchanges
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Re: Smallest and largest freeflow interchanges
For your pleasure ..... these are all in the vicinity of Cagliari:
1. A 'squashed' freeflow GSJ
2. A freeflow GSJ which appears to have been built using as many existing roads as possible!
3. An incredibly compact urban GSJ, which is freeflowing apart from where the red slips meet the yellow carriageway
Re: Smallest and largest freeflow interchanges
I guess both of these would technically count as giant freeflowing interchanges, because the carriageways on the route passing through the junction are separate for kilometres before and after the meeting point with the connecting route:
A10-A26
A7-A12
A10-A26
A7-A12
Re: Smallest and largest freeflow interchanges
That reminds me very much of the Ilford junction on the North Circular, which is of a similar design, although the slip roads cross one another at grade. Ilford_Bridge_Interchange
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Re: Smallest and largest freeflow interchanges
The Périphérique has some exceptionally compact freeflows as well:
Rome's A90 (formerly the GRA) and the A14 around Bologna are also good places to look.
Rome's A90 (formerly the GRA) and the A14 around Bologna are also good places to look.
Re: Smallest and largest freeflow interchanges
Scotstoun junction, in Glasgow, which I had a very small part in designing, is about the most compact I know for what it does
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Re: Smallest and largest freeflow interchanges
It certainly seems smaller than the Headless Cross cloverleaf.Chris Bertram wrote: ↑Fri Jul 10, 2020 15:33 The remaining cloverleaf in Livingston is pretty compact.
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Re: Smallest and largest freeflow interchanges
Certainly more ambition in this interchange design than in most junctions.
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Re: Smallest and largest freeflow interchanges
I like that junction. Wonder why it wasn't made full access?
Re: Smallest and largest freeflow interchanges
The missing movements are easily covered by roads to the west I think and the trouble of threading those movements through the park was presumably too much hassle.A42_Sparks wrote: ↑Mon Jul 13, 2020 18:30I like that junction. Wonder why it wasn't made full access?
Bryn
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She said life was like a motorway; dull, grey, and long.
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Terminally cynical, unimpressed, and nearly Middle Age already.
She said life was like a motorway; dull, grey, and long.
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Re: Smallest and largest freeflow interchanges
This one in Basel seems to squeeze as many movements as possible! The A2/A3 multiplex runs east-west, while the A18 runs through it north-south.