M4/M5 Almondsbury/Filton 'Improvements'

[DB617]

This scheme has now begun to reduce the ERA intervals and install complete concrete barrier between Filton and Almondsbury on the M4. It's currently operating as narrow lanes in both directions on the M4, with LBS4 out of commission. On Thursday night the severe congestion from the M32 junction merge backed up to Tormarton - a distance of over 6 miles.

I wonder if it would have been sensible to change the M32 to a lane drop and gain for the duration of the works and leave two lanes across the overbridges - a significant amount of traffic leaves and joins there, being an urban motorway link, and the junction would frequently back up awfully due to poor merging when LBS1 was closed. That said, I can't help thinking - as is often the case with the Bristol motorways - that if drivers would leave sensible gaps and merge in turn properly, it wouldn't be quite so disastrously slow at the join (with the exception of M5N > M4W which is an absolute atrocity of a merge anyway). I think Balfour Beatty have made a mess of this one and could have given a little more thought to the TM layout.

It's quite frustrating, really, that at the end of this (supposedly) 9 months of the motorway being unusable, the layout will be essentially exactly the same, rather than being reconfigured to ALR, and we will have to endure it all again in the future.

Strange thing is, I almost ended up getting a placement on the scheme before taking a job in Bath instead, which is why I now have to fight my way between the Avon cities through this mess every day.

[jackal]

Yes, it's the remnant of one of the RIS2 ALR schemes: "M4 junctions 19 to 20 and M5 junctions 16 to 17 upgrade dynamic hard shoulder running to all lane running".

However, in this case there was always intended to be a follow on RIS3 scheme called "Severn resilience package": "Developing a package of possible improvements to sections of the M4, M5 and M32 motorways on the eastern side of the Severn Crossings near Bristol to tackle current and future congestion levels following the 2018 removal of the tolls to cross the Severn bridges". Disruption might be reduced if they combine the ALR conversion with the resilience package.

[DB617]

There are definitely things that could be done. D3ALR gaining a lane at the interchange down to the M48 or even to the M49 would be a massive improvement. The current asymmetric arrangement with the 5 lane down to 2 merge is a bugbear of mine on such a major junction, a hold over from when the entire M4 west of Almondsbury to Newport was D2M - now it's simply dangerous and unnecessary. 'Match days' and major events in Cardiff have bad knock on effects in Bristol and the situation will be similar when the YTL Arena opens at Filton Airfield.

[JackieRoads]

Could someone actually improve the M4 & M5 interchange, and Hambrook & Frenchay, right in Fantasy Maps & Ideas thread? (Don't forget J16)

[DB617]

Oh, wouldst that I couldst (i.e. Had the skills that you people have). I have spent many an hour doing fantasy roads in my head. Only time I've ever drawn one was in Civil 3D and only because a Professor insisted. Oh, and it was a cycleway.

[Owain]

...
It's quite frustrating, really, that at the end of this (supposedly) 9 months of the motorway being unusable, the layout will be essentially exactly the same, rather than being reconfigured to ALR, and we will have to endure it all again in the future.

Strange thing is, I almost ended up getting a placement on the scheme before taking a job in Bath instead, which is why I now have to fight my way between the Avon cities through this mess every day.

I must be starting to sound like an old man these days, but I can remember the Almondsbury stack from when there were overtaking lanes instead of the hatched-out areas on all of the slips - including the one from M4(E) to M5(S) and A38 ... and you didn't necessarily come to an abrupt halt where the traffic merges from M4(W) to M5(S) either.

And I'm not just talking about being old enough to remember it as a kid, but old enough to have used the narrow overtaking lane to pass... an Austin Metro was a lot borrower than an Audi Q7, and would fit with no trouble if you had the nerve!

It depends where you're going from in Bristol and where you're going to in Bath, of course, but under the circumstances you might well find that the A4, A431 or A420 serve you better between Bristol and Bath. From Frome (where I lived until a decade ago) to Bristol, there wasn't really much between using the A4 or the M4 as far as time were concerned. I was probably a fool for not considering the unclassified roads from Frome and the A37 thereafter, but I never really settled in that town. Having to commute to Worcester didn't help, and the A46 and M4 were nightmarish!

[WHBM]

I must be starting to sound like an old man these days, but I can remember the Almondsbury stack from when there were overtaking lanes instead of the hatched-out areas on all of the slips

Well I can remember it when it wasn't even complete !

The centre structure was all built as one, but the M5 northwards wasn't opened until some years after the rest, so that level, plus its slips, were left unsurfaced.

Regular misdirections still occur with the adjacent A38 J16 on the M5, and the multiple divergences, made worse now the short weaving section is 4 lanes (in the beginning it was just two wide lanes). Westbound London to Exeter find they end up down at the A38 roundabout, while eastbound Exeter to London make the Almondsbury exit, know they then have to keep right for the split, and find they are back on the M5 northwards

[Owain]

I must be starting to sound like an old man these days, but I can remember the Almondsbury stack from when there were overtaking lanes instead of the hatched-out areas on all of the slips

Well I can remember it when it wasn't even complete !

The centre structure was all built as one, but the M5 northwards wasn't opened until some years after the rest, so that level, plus its slips, were left unsurfaced.

Regular misdirections still occur with the adjacent A38 J16 on the M5, and the multiple divergences, made worse now the short weaving section is 4 lanes (in the beginning it was just two wide lanes). Westbound London to Exeter find they end up down at the A38 roundabout, while eastbound Exeter to London make the Almondsbury exit, know they then have to keep right for the split, and find they are back on the M5 northwards

Ha - somebody always has to go one better! Can't compete with that...

My dad did have an old map that showed the M5 'starting' there in an obviously part-built version of the later completed junction and heading only south, but I'm not old enough to remember the 'missing link' of the M5 missing through Gloucestershire.

[Steven]

My dad did have an old map that showed the M5 'starting' there in an obviously part-built version of the later completed junction and heading only south, but I'm not old enough to remember the 'missing link' of the M5 missing through Gloucestershire.

You mean something like this??

Though once again I'm reminded when looking at that that the M4 is more north-south at that point, and the M5 is more east-west; the exact opposite to the expections of the alignment.

[DB617]

It depends where you're going from in Bristol and where you're going to in Bath, of course, but under the circumstances you might well find that the A4, A431 or A420 serve you better between Bristol and Bath. From Frome (where I lived until a decade ago) to Bristol, there wasn't really much between using the A4 or the M4 as far as time were concerned. I was probably a fool for not considering the unclassified roads from Frome and the A37 thereafter, but I never really settled in that town. Having to commute to Worcester didn't help, and the A46 and M4 were nightmarish!

I travel from Bradley Stoke to Claverton - bit of a trek, though not as bad as to Worcester. I use the A431 through Kelston and then head up towards the ring road through Oldland Common and Oldland Parish quite often when there are traffic problems on the M4, or as I found in my first few months of employment, at Cleveland Bridge. (there's always something on this particular commuter route!) The A46 is a nightmare as well, with Cold Ashton roundabout being awfully small for such a major crossroads, and far too many drivers playing bumper cars at Freezinghill Lane and Dyrham Park.

I find the A4 to be a mixed bag. The lack of a Saltford bypass is a big issue, and it can vary from 2 minutes in slow traffic to near stationary - mostly owing to how many drivers decide to let people go into and out of the side roads. When the M4 is busy, the three or four route options are so closely spaced in terms of ETA that I tend to just go with whichever is recommended by Google Maps at 10 to 4 when I leave work.

[Owain]

My dad did have an old map that showed the M5 'starting' there in an obviously part-built version of the later completed junction and heading only south, but I'm not old enough to remember the 'missing link' of the M5 missing through Gloucestershire.

You mean something like this??

Though once again I'm reminded when looking at that that the M4 is more north-south at that point, and the M5 is more east-west; the exact opposite to the expections of the alignment.

That's exactly it!

I liked the way they split the M5 to provide access to the two sets of slips for the M4 and A38 respectively, and I noticed as a kid that those bits were in place before the M5's central line.

It was probably a great layout before the kind of traffic levels that pass through there now...

I travel from Bradley Stoke to Claverton - bit of a trek, though not as bad as to Worcester. I use the A431 through Kelston [ ...] I find the A4 to be a mixed bag. The lack of a Saltford bypass is a big issue, and it can vary from 2 minutes in slow traffic to near stationary - mostly owing to how many drivers decide to let people go into and out of the side roads. When the M4 is busy, the three or four route options are so closely spaced in terms of ETA that I tend to just go with whichever is recommended by Google Maps at 10 to 4 when I leave work.

I can't help with Bristol - I was born there, but to this day it has the unique distinction of being (this is official) The Only Place Where I Ever Get Lost.

Whether you come into Bath on A4 or A431, for Claverton I'd be tempted to use the road that starts at the A4/A39 roundabout and passes round the south side of Bath, through Odd Down and Combe Down, and then down Brassknocker Hill. On Brassknocker you'd be going in the opposite direction to the commuter traffic, so it should be a hoot!

[JammyDodge]

I have done a diagrammatic map of a "Severn Approach" plan

This would separate the mainline M4/M5 traffic from Bristol traffic, effectively creating collectors, however this would create a whole new motorway, which I would number the M32, renumbering the current M32 to the M321, as it will become a spur off of this new stretch
This would also extend the M48 to connect to a new multiplex, where the M48 and M5 connect to the new M32
There would also be some renumbering of junctions.
What is currently M5 J15 would become J16, with the new J15 being the exit for the M32. J17 would move south to the diverge for the M32
The M4 junctions largely stay the same. The M48 is interesting, as I am not sure if the M4/M48 multiplex would be labelled J0, as the M48 would now start at the M32 multiplex

Some of the reason for the design is that I mainly wanted to leave the current Almondsbury interchange intact, during construction at least, which is why new roads are largely routed around it

[DB617]

Whether you come into Bath on A4 or A431, for Claverton I'd be tempted to use the road that starts at the A4/A39 roundabout and passes round the south side of Bath, through Odd Down and Combe Down, and then down Brassknocker Hill. On Brassknocker you'd be going in the opposite direction to the commuter traffic, so it should be a hoot!

That's one of the route options which comes up. If it wasn't for the problems in Saltford, it would be an excellent route and an easy enough drive. The only issue is the awful double mini roundabout followed by the roundabout for the road to Peasedown, which backs up all the way out of Combe Down towards Claverton. Traffic-wise, Bath is just a nightmare. Something to do with the complete lack of a bypass... appropriate for the gateway to Somerset.

[Owain]

I have done a diagrammatic map of a "Severn Approach" plan ...

That would be mightily impressive, but at Alconbury you have the urban area pressing up close to the existing junction on the SE side, and a golf course pressed up against it on the NE side.

I wouldn't be averse to bulldozing urban areas or tarmacking over golf courses if required, but I think a lot could be achieved by giving Bristol a proper motorway ring road to the south and east.

Part of the existing A4174 could be used for this purpose, and as well as relieving the existing M4/M5 to some degree, it could also provide much better access to Bristol Airport.

I'd always thought that Bristol Airport was the most inaccessible airport in the country, until I discovered Leeds-Bradford!

[WHBM]

My dad did have an old map that showed the M5 'starting' there in an obviously part-built version of the later completed junction and heading only south, but I'm not old enough to remember the 'missing link' of the M5 missing through Gloucestershire.

The M5 didn't go very far south then - Almondsbury J15 to Avonmouth J18 was the only complete part for quite some years - in fact I think it was initially only a couple of miles Almondsbury to Cribbs Causeway J17. The M5 bridge over the Avon had design issues and didn't open until years after the rest. We have discussed before the resulting convoluted through route(s), and lack of signposting, through Bristol.

The through M5 route at the stack is on level 3 of 4. The key problem here has always been that both M4 and M5 through there are just two lanes, with a narrow hard shoulder preventing grabbing that as a running lane, and the support columns stopping any widening.

[Enceladus]

I drove through the M4/M5 Almondsbury interchange with my father and an English business associate of his (the latter was doing the driving) in the early 1990s on a journey from London to Cardiff. At the time, I was very impressed with this 4 level stack junction - all the bridges wowed me and it was built way back in 1966!

Of course, back in 1992 there were only about 5 short stretches of motorway (including the first section of the M50 Dublin ring) in RoI and precious little DC on the national primary network.

These “improvements” at Almondsbury - a very high capacity interchange - are really just kicking the can down the road and do not really address the fact that the British motorway system is badly overloaded and cannot cope with population and traffic growth.

I’m sure it might be possible to enhance capacity in minor ways, but high quality rail solutions for inter city travel need to be looked at, as does suppressing local traffic using the junction via modal shift to rail. Also a Southern and Eastern ring motorway of Bristol would probably provide a lot of relief.

[Steven]

My dad did have an old map that showed the M5 'starting' there in an obviously part-built version of the later completed junction and heading only south, but I'm not old enough to remember the 'missing link' of the M5 missing through Gloucestershire.

The M5 didn't go very far south then - Almondsbury J15 to Avonmouth J18 was the only complete part for quite some years - in fact I think it was initially only a couple of miles Almondsbury to Cribbs Causeway J17.

This was the original stretch, known as M5 Filton Bypass.

If you step through the annual One Inch layers, you can see the changes happening.

[Owain]

My dad did have an old map that showed the M5 'starting' there in an obviously part-built version of the later completed junction and heading only south, but I'm not old enough to remember the 'missing link' of the M5 missing through Gloucestershire.

The M5 didn't go very far south then - Almondsbury J15 to Avonmouth J18 was the only complete part for quite some years - in fact I think it was initially only a couple of miles Almondsbury to Cribbs Causeway J17.

This was the original stretch, known as M5 Filton Bypass.

If you step through the annual One Inch layers, you can see the changes happening.

Wow! I'd never realised that the M5 was Bristol's first motorway, having assumed that the section you linked to before was built in conjunction (no pun intended) with the M4.

[WHBM]

This was the original stretch, known as M5 Filton Bypass.

It was the second attempt at a Filton bypass. If you look at the map a late 1930s road doing so, with the same local name, on the map the B4057, had been cut through about 10 years after building by the extension of the runway at Filton airport for the construction of the grand Brabazon airliner there, as can be made out. There must have been some agreement with the government that what later became the M5 here would be built as a substitute. Though by its alignment it's not really a Filton bypass of the A38.

[Steven]

It was the second attempt at a Filton bypass. If you look at the map a late 1930s road doing so, with the same local name, on the map the B4057, had been cut through about 10 years after building by the extension of the runway at Filton airport for the construction of the grand Brabazon airliner there, as can be made out.

We have a great article on the original Filton Bypass on the SABRE Wiki.

Whilst on SABRE Maps:
Now you see it...

...Now you don't.