M4 - M5 - A38 Comments

How about this?

Build a half diamond from the A38's bridge over M4 (the bridge is already wide enough for the job), with slip roads facing SE, running alongside but not joining M4E (a la A414/M1 junction), until they join the slips roads to and from the M5. Traffic from M5N wanting to reach J16 would only have to cross SW - S Wales traffic, but since M49 that is easy.

Then you can close off the existing access between J16 and M5N, allowing two lanes for the whole length of the sliproads between London and the SW. J16-M4 traffic is unaltered, but now has more time and less competition for space to negotiate the junction.

At the same time, ideally, the M5 should be upgraded to 4 lanes each way from J17 to J15 (splitting 2 for M4, 2 for M5), and the M4 likewise desperately needs a 4th lane all the way to J19 (it only narrows to 3 lanes for about a mile currently!).

Almondsbury residents would probably take the extra traffic through their village in exchange for safer access to the M5 and M4!

P.S. This scheme could also serve as a decent temporary diversion to create the space for grade separating M5N-J16 from M4-M5 traffic, if that ultimately proved necessary.

Fixing this junction would be extremely easy. As suggested, a braided junction would be the best answer.

The model I'd suggest for it is the M8-A720 junction - two slip roads go around the M8 junction to access the the A71.

Similarly, the south-facing sliproads from the M4 can be routed around the A38 junction.

I moved to Almondsbury about 4 months ago and I travel all over the South West for work and this is still the worst part of any journey.

People who use only the M5/M4 think this is bad, try going Northbound from the A38 and attempt to get onto the M5 on any morning when the M4 is jammed down to the M32. Whilst the junction is awful, the thoughtless and horrendous driving tendancies by impatient drivers coming off the M5(N) to join the M4 Eastbound make this junction an absolute death-trap. To get onto the M5 Northbound you have to effectively cross a single file queue of traffic trying to get onto the M4E distributor road, so whilst you cross that first line of traffic to get into clear air for the M5, you will get some idiot come flying down the outside trying to tuck into the M4E collector lane at the last minute and thus taking me or someone else out!!!

The only suggestion I can think of is that M5 traffic should have a separate way to join the A38 at Junction 16 and let the M4 traffic flow freely into either the A38 or the M5.

A lot of traffic should be removed from this junction all together by building a new motorway east of Bristol, this could connect with the mystery junction on the M4 between Bath and the M32. It could continue north to meet the M5 closer to Michaelwood Services and south to meet the M5 near Clevedon. Any traffic heading to and from London could then miss this busy junction all together.

The M49 does a similar job for traffic travelling between the South West and Wales and I imagine it contributes massively to reducing congestion at Almondsbury (apart from the silly roundabout junction where it meets the M4 - Doh!)

Part of the problem was that the M5 between now junctions 16 and 17 was built as a small bypass of Filton and predates the Almondsbury interchange.

It is akin to the M60 junctions 11 to 13 situation where the local junctions 11 and 13 were part of the original Stretford - Eccles bypass and predate the major interchange at junction 12 (M60, M62, M602, former M63) which had to be shoehorned in afterwards and the existing bypass widened.

Mark has a valid point about sat-navs - they struggle with collector carriageways. I have witnessed them go haywire with the much larger Worsley Braided Interchange.

As for the junction being close - it's an unfortunate by-product of early 1960s thinking that traffic volumes would cope with such short distances - look at how close together junctions in new towns are for example.

It would be hellishly expensive but some kind of slip road braiding would be helpful.

I have used this junction many times, but it was on the last usage I discovered that sat-navs do not understand how the C-D lanes work! It told me to keep right after turning off. It was only AFTER I was part the gore did I realise the lane I was in took me back to the M5. My father-in-law made the same mistake using the same sat-nav.

The problem is the A38 junction - why was it built so close?

I had to use this junction for the first time recently while returning from Reading, travelling M4 westbound to M5 southbound. And I can quite agree that the C/D carriageway I had to use is a mess!

Since I knew about this junction in advance, I knew I had to move to the right, but there was no indication of where, and I was about to move into the lane that just joined from M4 eastbound when I realized that would be pointless.

It could really do with some advance signage, and longer hatchings, since the lanes are ridiculously wide here for the most part.

For a more ambitious suggestion, I suppose if the M5 was realigned slightly to the northwest there might be room for a pair of one-lane braided sliproads from M5N to the J16 roundabout and back.

Alternatively, scrap the entire junction 16, dual and classify Bradley Stoke Way, and have that link up to a new roundabout interchange with the M4 about a third of the way between this and the M4-M32 junction (such a road could link up to the B4427 too to avoid the motorway restriction problems).

Regarding Andy's idea;

I'm afraid it simply wouldn't work. First, there is no room for a bridge between J16 and J17 - the land to the south of the motorway in particular is very heavily developed. There's also no room for the sliproads on the motorway itself - it would just cause even worse weaving for the whole stretch between the M4 and Cribbs Causeway.

When a road is particularly dangerous (as described) it is sometimes worth doing particularly idiotic things just to make it safe.
One suggestion for you to rip apart: Remove the east on / off slip of the A38 onto the M5. This fixes the short interchange problem.
Build a new bridge a sensible distance west along the M5 allowing westbound M5 traffic to turn and come back eastbound. This allows all traffic to access everything, without the short interchange.
It also reduces the complexity of the roundabout, so some of the traffic signals can be scrapped which will ease the flow of traffic. Also consider adding a 4th lane for the entire section between the M4 and new bridge I suggested.
This 4th lane (on the left) is for non M5 traffic, either joining or leaving and connects to the existing M4 connections.
I don't believe I have ever driven through this junction. So perhaps I am not taking something into consideration.

My father was part of the team that originally surveyed the junction. He has told me that originally it was supposed to be a 'butterfly' type, but budget constraints reduced it to the 'cross' shape it is today.

Having used this junction in all directions for the best part of 20 years, I am absolutely astounded that there isn't at least one fatality a month on this junction. Almost every time I pass through it I see a near miss, usually the result of people being in the wrong lane and lurching across the hatched area at the last minute.

As this is now on my way home every week, I feel compelled to give my six penneth. The whole thing suffers from a capacity inadequacy. Two lanes cannot handle the southbound (or northbound) M5 traffic during peak hours (same is true of M4 east or west). An extra lane is the only answer (two hopes), or even better a junction diversion route linking the M49 to the M5 near to Michaelwood (more chance of winning the lottery).

James' plan would also reduce the possibility of mistakes - travelling from the northbound M5 to the eastbound M4 you need to take the slip road on the left and then bear right. If you bear right too soon however, you end up back on the northbound M5 - it's a long way up to J14 before you can turn round and try again.

There is an obvious cheap-and-nasty solution: build a North-facing half diamond on the M5 at Hortham Lane (the unclassified road bridging the M5 immediately north of all this), stick a roundabout in (or let's be really pathetic: paint a mini-roundabout!) where that joins the A38, then close the links between the M5(N) and the C/D roads. That should simplify things enough to keep it moving.

When M5 J16 was built, the A38 was a single carriageway road and the surrounding area was fields. Since then the whole area has been massively developed and the A38 has become a major access route into Bristol. J16 is a basic roundabout junction and is quickly followed on the A38 by another roundabout. As both of these are now traffic light controlled to cope with the load, it is no wonder the whole complex is completely overloaded.

Unfortunately, as the whole area is developed, any improvements would require large scale demolition and so is unlikely ever to happen. One way to improve this junction, particularly from the summer Saturday queues, would be to provide another route from the M4 to the M5 around the east and south side of Bristol, but penny pinching on the A4174 has probably ruled out that idea.

Lastly, the M5 north of the Almondsbury interchange didn't open until 1971, so for 5 years, the north side sliproads lead to a field!

Luckily, if you are coming from the M4, or want to do M5S-M4 in any direction, one can use M5 j18a and the M49 (pathetic as it is;) ) to bypass this Bad Junction's sliproads. You'd just be going straight through the middle on the M4 ! :)

What isn't mentioned in the article is that, next year, the M5 is getting Active Traffic Management. Whilst all sources state J17 to J15 (Cribbs Causeway to the M4), I can't see how it is physically possible to have ATM around here. This may cause complete and utter chaos, which could potentially kill off ATM for good.

And whilst the M5 has the 'summer Saturday' reputation, it is getting to the stage where the Bristol section is gridlocked all year round. The tourists start at Easter, and don't stop until September. Cue the inevitable annual roadworks on the Avonmouth Bridge, which almost always cause queues back to at least Almondsbury, if not further. Once they're finished, you've got Christmas - and the miles of queues for Cribbs Causeway Shopping Centre. Whilst most traffic uses J17, J16 is a popular back route into the complex, which adds to this junction's problems. After the January sales, you might have a brief respite until Easter comes once again.

As mentioned, you will have the ATM works to add to this next year, which could be fun.