Does a road connecting with a motorway have to be a motorway??

[Berk]

This may have been covered many years ago. There was an assumption, in the early days, that any road which connected directly with a motorway also had to be a motorway. Accordingly, the A308(M) was built as a motorway, because it had to be.

This is no longer the case, so why did this assumption last as long as it did??

[c2R]

It was that a road that led inescapably to a motorway should also have to be a motorway.

Most are, because it makes sense.

[wrinkly]

At one time the only exceptions were if there was a roundabout where you had the option of doubling back. But in the last decade or more, further exceptions have appeared, with Catthorpe being the biggest and most obvious.

[Berk]

Surely that would mean that city ring roads would be reclassified as motorways as well - if that’s where they end up?? Like the A5460 (partly started off as a motorway), or the A1139 - only leads to a motorway at the western end.

Where is the line drawn??

[wrinkly]

Where is the line drawn??

I guess that that nowadays it probably depends who's designing the scheme.

[Bryn666]

Inescapably means without any option to leave... there was no operational reason to de-specialise the A46M - but traffic signal controlled merges onto the now A5460 probably upset the standards wonks.

[Johnathan404]

A SABRE member walks into a bar. The barman says "I'll be with you in a moment". The SABRE member says "but which zone do I wait in?".

Where is the line drawn??

I guess that that nowadays it probably depends who's designing the scheme.

Has it not always been like this? M3 J6, M4 J4, M5 J24, M6 J35, M20 J5 and J8, M25 J4, M27 J2... they all apply this "rule" differently.

[wrinkly]

Has it not always been like this? M3 J6, M4 J4, M5 J24, M6 J35, M20 J5 and J8, M25 J4, M27 J2... they all apply this "rule" differently.

Except for one that I didn't know about until recently - is it on the A167(M) in Newcastle? - there were until relatively recently no places where you could be on an all-purpose road heading to a motorway with no possibility of escape (where doubling back counts as escape if it's possible at all, and where we ignore, for example, the few yards inside a hamburger).

Thus to go over your listed examples:

M3 J6, M4 J4, M20 J8, M25 J4, the spur is a motorway

M5 J24, M20 J5, M27 J2, all conventional motorway junctions, roundabout is AP and connects more than one AP road

M6 J35, the spur is a motorway and was once the mainline M6.

All the above are conventional. But in more recent years we've had the unconventional:

M1/M6/A14 since the upgrade, several miles of A14 leading inevitably to motorways with no escape (discussed ad nauseam in the relevant thread)

M56 west end since its upgrade, several hundred yards of A494 leading inevitably to M56 with no escape (incidentally I see the OS still calls it A5117 and shows the start of motorway sooner than is the legal situation)

A1(M) Doncaster bypass at Blyth since its upgrade, several hundred yards of A1 leading inevitably to A1(M) with no escape (here again the OS shows the start of motorway sooner than is the legal situation)

We've also had a temporary similar situation on the A1/A1(M) at Hook Moor, and we have a mirror situation at the south end of the M77 where the motorway ends at a point where there is no joining AP road (but there is a diverging slip road).

[lefthandedspanner]

Surely that would mean that city ring roads would be reclassified as motorways as well - if that’s where they end up?? Like the A5460 (partly started off as a motorway), or the A1139 - only leads to a motorway at the western end.

Where is the line drawn??

If the only way forward is onto a motorway, e.g. M898 south of junction 1, where the next junction leads inevitably onto the M8.
The western end of A1139 is a roundabout where it meets A605, A1 and A1(M), so there's no need for any of it to be a motorway.

Except for one that I didn't know about until recently - is it on the A167(M) in Newcastle? - there were until relatively recently no places where you could be on an all-purpose road heading to a motorway with no possibility of escape (where doubling back counts as escape if it's possible at all, and where we ignore, for example, the few yards inside a hamburger).

If memory serves, for a few years in the late 90s/early 2000s the Micklefield bypass on the A1, now upgraded to A1(M), used to be a spontaneous motorway at the northern end.

[wrinkly]

If memory serves, for a few years in the late 90s/early 2000s the Micklefield bypass on the A1, now upgraded to A1(M), used to be a spontaneous motorway at the northern end.

I was thinking of that when I said

a temporary similar situation on the A1/A1(M) at Hook Moor

[Chris5156]

Has it not always been like this? M3 J6, M4 J4, M5 J24, M6 J35, M20 J5 and J8, M25 J4, M27 J2... they all apply this "rule" differently.

Thus to go over your listed examples:

M3 J6, M4 J4, M20 J8, M25 J4, the spur is a motorway

M5 J24, M20 J5, M27 J2, all conventional motorway junctions, roundabout is AP and connects more than one AP road

M6 J35, the spur is a motorway and was once the mainline M6.

All the above are conventional. But in more recent years we've had the unconventional... (snip)

Consider also, though, M2 J4, a non-motorway spur to a roundabout interchange where no other AP roads connect. It’s been like that since the 60s, so there have always been exceptions to the “normal” way of doing things. But your general point - that “spontaneous motorways” are a relatively modern confection - is absolutely true.

The short answer to Berk’s question is that it’s often hopeless to try and seek out a logic or a watertight rule that explains the way things work on the UK road network. This is one of those times.

[Helvellyn]

We had the A6144(M) which is now just the A6144, doesn't go anywhere other than the M60 but still got downgraded several years ago. It's not quite inescapbaly to the M60, you could turn round at the end and go back (at least I assume the roundabouts aren't under motorway restrictions any more but I can't remember for certain), but there's nowhere else you can get to from it.

[scragend]

We had the A6144(M) which is now just the A6144, doesn't go anywhere other than the M60 but still got downgraded several years ago. It's not quite inescapbaly to the M60, you could turn round at the end and go back (at least I assume the roundabouts aren't under motorway restrictions any more but I can't remember for certain), but there's nowhere else you can get to from it.

I think that was downgraded when the roundabout was re-modelled. It used to be quite tight, so long vehicles would struggle to get round it to turn back, which isn't the case now, so there is more of an escape than there was.

I agree though, it's kind of pointless going down it if you don't intend to join the M60 (unless you end up there by mistake).

[Johnathan404]

Except for one that I didn't know about until recently - is it on the A167(M) in Newcastle? - there were until relatively recently no places where you could be on an all-purpose road heading to a motorway with no possibility of escape (where doubling back counts as escape if it's possible at all, and where we ignore, for example, the few yards inside a hamburger).

(Arguably M32 J3)

Yes, sorry, I agree that truly spontaneous motorways are a recent trend and probably the consequence of a lack of understanding (or financial/paperwork laziness). I sometimes wonder whether we care about this too much, so long as it's clearly signed at the point of no return (which even A14 J1 is now), does it really matter where the regulations start?

I'm sure throughout history there have been some dodgy examples, even if they weren't truly spontaneous. Where did the regulations kick in at M1 J8 before the roundabout was built? Maps show it as being all purpose right up to a gap in the barrier where the slip roads split, which may not be correct. Likewise M20 J5 when it was a trumpet with a farm to the north.

[owen b]

We had the A6144(M) which is now just the A6144, doesn't go anywhere other than the M60 but still got downgraded several years ago. It's not quite inescapbaly to the M60, you could turn round at the end and go back (at least I assume the roundabouts aren't under motorway restrictions any more but I can't remember for certain), but there's nowhere else you can get to from it.

M1 J10-10A is similar. It used to be a motorway spur, but since the flyover was put in at 10A 2014/15 it's part of the A1081.

[Al__S]

Except for one that I didn't know about until recently - is it on the A167(M) in Newcastle? - there were until relatively recently no places where you could be on an all-purpose road heading to a motorway with no possibility of escape (where doubling back counts as escape if it's possible at all, and where we ignore, for example, the few yards inside a hamburger).

(Arguably M32 J3)

Whilst motor traffic can only proceed onto the Motorway there, there's pedestrian access right up the junction and cycle traffic can turn right across the island and head south. It's a very odd junction though!

Which leads me to- in any of the other examples, are there footways and/or cycle access within (or even level across) the "inescapable" road's highway boundary up to where the blue signs kick in?

[c2R]

We had the A6144(M) which is now just the A6144, doesn't go anywhere other than the M60 but still got downgraded several years ago. It's not quite inescapbaly to the M60, you could turn round at the end and go back (at least I assume the roundabouts aren't under motorway restrictions any more but I can't remember for certain), but there's nowhere else you can get to from it.

Exactly - I personally don't see the point in despecialising it. For similar reasons there is no point to despecialising the walton summit motorway or the Orrell Interchange link.

[Nicholas]

Which leads me to- in any of the other examples, are there footways and/or cycle access within (or even level across) the "inescapable" road's highway boundary up to where the blue signs kick in?

I can go one better!

[PhilC]

I remember the M10 being downgraded to the A414. At the M1 end there is a slip road for non-motorway traffic to leave without going on the motorway. However, the M45 was not downgraded, presumably because there is no way of avoiding the motorway.

[c2R]

That, and again, there's no real need for it to be downgraded, providing as it does a motorway link between Coventry and the M1 south.

I wouldn't have downgraded the M10, although I would have renumbered it as A414(M)