Grade-separated Junctions on Single Carriageway Roads

[ThelwallViaduct]

Spotted a trumpet-style interchange between the A45 and A361 at Daventry earlier today.

Free-flowing interchanges for single carriageway roads are pretty rare in the UK - only other one I could think of was on the A483 south of Wrexham and even here the major road is dual carriageway north of the junction.

Any others? I'm primarily looking for junctions in which the major road is single carriageway, and flows freely through the junction (rather than, for example, two roads which pass over each other through a bridge, but are connected by a link road with at grade junctions). Cheers!

[orudge]

A9 / A86 at Kingussie is a GSJ between two single carriageway roads. It's perhaps not as free-flowing as some of the other examples though (there are deceleration lanes on the A9, but no acceleration lanes).

[bart]

The Dalkeith bypass is S2 with short lengths of D1 for the GSJs, which are (presumably) only there to stop people trying to do moronic things.

[ForestChav]

There are a couple on the A616 between the M1 and A628, with the A629 and A6102, from the perspective of the A616 you can drive through without stopping...

[PeterA5145]

One of the earliest was this one on the A533 Runcorn Spur Road, which opened in 1961. It has since been downgraded to the B5155, lost one of its four slip roads, and is now one-way westbound across the bridge.

[wrinkly]

only other one I could think of was on the A483 south of Wrexham and even here the major road is dual carriageway north of the junction.

There's a roughly similar one at the dual/single transition on the A6 Chapel-en-le-Frith bypass (it's the junction with the former A625, which has become a yellow road after being geologically severed at Mam Tor).

I think I have an old map suggesting a similar one at Droitwich but current maps show the dual carriageway continuing through the junction and ending shortly after it.

[Chris Bertram]

I think I have an old map suggesting a similar one at Droitwich but current maps show the dual carriageway continuing through the junction and ending shortly after it.

That'll be the junction with the A4133 for Ombersley and Holt Heath. A38 is dual through the junction and single shortly after to the south.

[JohnnyMo]

Does this count -- A1000 Hatfield or this one A1000 Welwyn Does anyone have any idea what the original layout was ?

[wrinkly]

I think I have an old map suggesting a similar one at Droitwich but current maps show the dual carriageway continuing through the junction and ending shortly after it.

That'll be the junction with the A4133 for Ombersley and Holt Heath. A38 is dual through the junction and single shortly after to the south.

Landranger 150, edition A underscore asterisk, copyright 1980, revised 1976-7, major roads revised 1977, selected roads revised 1980, shows the dual carriageway ending at the point where the northern slip roads join/leave the mainline. Of course that could be another OS error or copyright trap.

Edition B, copyright 1991, revised 1989, major roads revised 1990, shows it as on today's maps.

[orudge]

The B7076 has at least one GSJ towards its southern end, a ghost of the old A74.

EDIT: Here it is.

[A9NWIL]

Here: https://www.google.co.uk/maps/@52.29083 ... e3!5m1!1e1
The A441 and A448 dual carriageways cross and are fully grade separated with one of I believe on two examples in the country of a fully 4 cloverleaf junction.

[SirKnoes]

Here: https://www.google.co.uk/maps/@52.29083 ... e3!5m1!1e1
The A441 and A448 dual carriageways cross and are fully grade separated with one of I believe on two examples in the country of a fully 4 cloverleaf junction.

I thought we were talking about single carriageway roads...

[wrinkly]

The B7076 has at least one GSJ towards its southern end, a ghost of the old A74.

EDIT: Here it is.

The one at your link involves a surviving bridge from what was originally a diamond junction on the old A74.

There are several places where the motorway was built alongside the old A74 dual carriageway and a side road was taken over both by a new bridge of several spans, then curving or linking round in various ways to connect to the former A74 (which with one carriageway removed became the B7076) on the side away from the motorway.

Some of these probably don't count as GSJs because the side road doesn't continue beyond the junction, but one or two perhaps do, for example the junction with the A709 at Lockerbie.

Similarly there's the junction between the A59 and the remains of the old A1 adjacent to A1(M) J47.

I'm not sure whether we're supposed to be counting junctions where there's a 2-way link road with a T-junction at each end, such as those just mentioned, or A75/B6357 at Annan or A75/A713 at Castle Douglas.

[brummie_rob]

Probably been posted in the past but here is an old one which originates from 1930 in Hanley: https://www.google.co.uk/maps/place/Sto ... d-2.179404

[jackal]

The most recent examples of 'Grade-separated Junctions on Single Carriageway Roads' or 'grade-separated junctions for single carriageway roads' that I'm aware of are these on the A68. The mainline is dualled for the duration of the junctions, however.

Some older GSJs that come to mind are this on the B1514 and this glorified private access on the A4.

Of course, in countries like Spain and Italy there are thousands of miles of grade-separated single-carriageway with their own cloverleafs and stackabouts.

[B1040]

Does this count -- A1000 Hatfield or this one A1000 Welwyn Does anyone have any idea what the original layout was ?

The Hatfield Junction is fairly recent. The Welwyn one is one of our earliest flyovers, but was not originally a GSJ. Access from the B1000 to the A1 was through the village to a T junction at the end of the bypass
http://www.sabre-roads.org.uk/maps/inde ... ,-0.18086,

[Johnathan404]

There are a few examples of flyovers with link roads, or full-on junctions with acceleration lanes (which do feel weird). My favourite GSJ of all-time is the Brighton Marina exit on the A259, where the through-route is mostly S2.

[jh1985]

How about this little number just north of Wetherby?

[WHBM]

A13 Lodge Avenue flyover in Dagenham, East London is single carriageway through the junction.

https://www.google.co.uk/maps/@51.53262 ... 312!8i6656

A316 Chiswick Flyover in West London is one lane linking single carriageway roads on each side.

https://www.google.co.uk/maps/@51.48558 ... 312!8i6656

[Rob590]

There's one on the A181 at Wingate, County Durham with the unclassified Salters Lane.