Isolated motorway networks

[Peter350]

I use this term to describe a motorway or group of motorways which are not connected to the rest of the UK network and therefore require you to use an all-purpose road to get between the two. Currently the only examples of these in Great Britain are the M2, A1(M) (Alconbury - Peterborough), A3(M) and the urban motorways in Manchester, Leeds and Newcastle. Not that long ago however, there used to be loads more examples of isolated motorway sections, a legacy from the early days of road building when motorways were known for being built in discontinuous sections. To help explain this better, I have listed some examples of previously isolated motorway networks below.

A1(M) (Barton - Washington), A66(M) and A194(M) were isolated from the rest of the UK motorway network until the A1(M) Leeming - Barton section was completed earlier this year.

M90 and A823(M) were isolated before the Queensferry crossing was built in 2017.

M8 & M80 (Eastern section), M9 & M876 until the M80 missing link was completed in 2011.

M8 & M80 (Western section), M73, M74, M77, M898 & A74(M) until the Cumberland Gap was completed in 2008.

M65 until it was extended in 1997

M27, M271 & M275 until the M3 was built through Twyford Down in the 90s.

The M3, M11, M20/M26, M23 and M40 were each isolated before the M25 was completed in the 80s. Seems really hard to believe to this day!

The section of M6 between Birmingham and Catthorpe is what I call the ultimate missing link, since when it was built, it joined up three previously isolated motorway networks, the M1, M5 and M6. Before then, there was no proper joined up motorway network in the UK, but since it was completed in 1972, the motorways it linked have become the core of the UK network. Of course, each motorway had numerous discontinuous sections in the early days.

What I would be interested to know is, at what time were there the most sections of discontinuous & isolated motorways in the UK?

[ScottB5411]

The M90 and A823(M) are still isolated, a small stretch of A90 separates the 2 sections of M90

[Peter350]

The M90 and A823(M) are still isolated, a small stretch of A90 separates the 2 sections of M90

Just checked it on the map. Seems odd though to leave it as all purpose when it was built at the same time as the Queensferry crossing. I thought it was built as motorway.

[c2R]

The best way of doing this would be to look at cbrd: http://www.roads.org.uk/motorway/chronology

I make it:
1958 - 1
1958 - 3
1960 - 7
1961 - 9
1962 - 11
1963 - 11
1964 - 12
1965 - 12
1966 - 15
1967 - 16
1968 - 20
1969 - 21
1970 - 23


I think I make the maximum as 1972 - 24 before everything starts really joining together...

[Euan]

I thought the A90 at Queensferry was a mapping error. So it turns out the new section of road between the A904 and the end of formerly the M9 spur is genuinely non-motorway. In that case most of the M90 is still cut off from the rest of the motorway network, but not by water!

[RickyB_uk]

I use this term to describe a motorway or group of motorways which are not connected to the rest of the UK network and therefore require you to use an all-purpose road to get between the two. Currently the only examples of these in Great Britain are the M2, A1(M) (Alconbury - Peterborough), A3(M) and the urban motorways in Manchester, Leeds and Newcastle.

Add the M67 and A1 (South Mimms - Baldock), since there's still no actual motorway-motorway connection between them, without using all-purpose roads.

The M57 was previously in this category until the M62-M57 loop was constructed.

The A1(M) Alconbury to Peterborough looks to be soon connected through to the A14(M), which in turn will connect to the M11 - so that'll be another gap closed. Will the South Mimms - Baldock section get closed by a look or sliproad from the M25 or by the construction of the Baldock - Brampton section first?

[Steven]

The section of M6 between Birmingham and Catthorpe is what I call the ultimate missing link, since when it was built, it joined up three previously isolated motorway networks, the M1, M5 and M6.

Two.

The section opening in 1972 was through Birmingham east of J7. The M5 and M6 connected together in the Black Country before that.

[James]

I thought the A90 at Queensferry was a mapping error. So it turns out the new section of road between the A904 and the end of formerly the M9 spur is genuinely non-motorway. In that case most of the M90 is still cut off from the rest of the motorway network, but not by water!

Is there any specific reason why the motorway wasn't connected? When I was driving through there last year seemed to make no sense having the small non-motorway gap between the motorway sections.

Why the new crossing is only D2M though is another issue!

[Steven]

I thought the A90 at Queensferry was a mapping error. So it turns out the new section of road between the A904 and the end of formerly the M9 spur is genuinely non-motorway. In that case most of the M90 is still cut off from the rest of the motorway network, but not by water!

It isn't cut off from the Special Road network though!

[paully]

Call this slightly pedantic, but there are two stretches of the M8 which are completely isolated from the rest of the motorway, the links below are for directions along these parts:
https://goo.gl/maps/kUtLvUWZuDC2
https://goo.gl/maps/qbkMb7vbUBn

Both of these used to be sliproads that merged onto the mainline, but now instead of merging they both exit at the next junction.

[nowster]

https://goo.gl/maps/qbkMb7vbUBn

Both of these used to be sliproads that merged onto the mainline, but now instead of merging they both exit at the next junction.

Oddly this has white signage and merges with the M8 off slip after the end of motorway signs. Given there's a minicab parked up on it (and some advertising trailers) in the GSV imagery, one wonders if it's actually under motorway restrictions.

[Bryn666]

https://goo.gl/maps/qbkMb7vbUBn

Both of these used to be sliproads that merged onto the mainline, but now instead of merging they both exit at the next junction.

Oddly this has white signage and merges with the M8 off slip after the end of motorway signs. Given there's a minicab parked up on it (and some advertising trailers) in the GSV imagery, one wonders if it's actually under motorway restrictions.

I think the blue chopstick sign at the entry from the airport is an incorrect replacement of the pre-1993 sign that will have been from when the old slip road was under motorway regulations.

[David D Miller]

I thought the A90 at Queensferry was a mapping error. So it turns out the new section of road between the A904 and the end of formerly the M9 spur is genuinely non-motorway.

Is there any specific reason why the motorway wasn't connected?

It's because the all-purpose A90 from Edinburgh has no public exit at the point where it joins the ex-M9 spur motorway and onto the new bridge approach road. There is a bus lane exit from the A90 onto the B800 (ex-A8000), but it's prohibited for other traffic to prevent rat-running through Ferry Muir. Similarly, while there is a bus-only route from the A9000 (ex-A90) Echline junction joining the A90 towards Edinburgh as a bus lane, there's no entry here for other traffic.

Because there's no alternative route provided for non-motorway traffic, the new A90 special road between the ex-M9 spur and the A904 junction is not designated as motorway.

[B1040]

The A1(M) Alconbury to Peterborough looks to be soon connected through to the A14(M), which in turn will connect to the M11 - so that'll be another gap closed. Will the South Mimms - Baldock section get closed by a look or sliproad from the M25 or by the construction of the Baldock - Brampton section first?

Off the top of my head, the A1 is remaining all purpose from Alconbury to Brampton Hut and the A14(M)

[Owain]

The M90 and A823(M) are still isolated, a small stretch of A90 separates the 2 sections of M90

Just checked it on the map. Seems odd though to leave it as all purpose when it was built at the same time as the Queensferry crossing. I thought it was built as motorway.

I thought the A90 at Queensferry was a mapping error. So it turns out the new section of road between the A904 and the end of formerly the M9 spur is genuinely non-motorway. In that case most of the M90 is still cut off from the rest of the motorway network, but not by water!

Is there any specific reason why the motorway wasn't connected? When I was driving through there last year seemed to make no sense having the small non-motorway gap between the motorway sections.

Why the new crossing is only D2M though is another issue!

Folks, there's a thread about the gap in the M90 here!

[ScottB5411]

Given the context of the thread, it's on topic discussion, despite the other thread.

[Peter350]

I think I make the maximum as 1972 - 24 before everything starts really joining together...

It would actually be 25. Although the M8 and M9 appear to be part of the same network, Newbridge Roundabout (where both motorways originally terminated) was built at-grade with an all-purpose road. This meant that the M8 was technically isolated from the M9 until the flyover was built several years later.

[Owain]

Given the context of the thread, it's on topic discussion, despite the other thread.

I posted it because I thought it might answer some of their questions!

[RickyB_uk]

The A1(M) Alconbury to Peterborough looks to be soon connected through to the A14(M), which in turn will connect to the M11 - so that'll be another gap closed. Will the South Mimms - Baldock section get closed by a look or sliproad from the M25 or by the construction of the Baldock - Brampton section first?

Off the top of my head, the A1 is remaining all purpose from Alconbury to Brampton Hut and the A14(M)

Not according to the map here.

[Glenn A]

The Scottish network until the M74 was extended. This was a self contained system of motorways that started at Abington and ended near Perth,