M40 - A46 - A429

Longbridge Island

Where is it?

M40 junction 15. The London-Birmingham motorway meets the A46, the main road linking Stratford-upon-Avon, Warwick and Coventry. This point is the southern end of the Warwick western bypass.

The junction has been remodelled since this page was written. The article below describes an earlier version of the junction.

What's wrong with it?

Yes, it's another overloaded roundabout interchange. Nothing unusual there — we have a three-lane motorway sailing through underneath while all hell lets lose up above. A little way further north-east, the A46 has three lanes each way as well, so it seems a little harsh to just bring it to a halt at the roundabout like this.

Why is it wrong?

This junction is an overloaded roundabout interchange with a twist. Yes, the extra entertainment value here is provided by the junction's history. Not so long ago, the A46 just stopped here at a roundabout, meeting the A429 and the Warwick southern bypass. The A46 was grade-separated already to the north, and this roundabout was built with provision for a flyover. You can still see the flared carriageways today.

In 1991, a cash-strapped government opened the M40 through here. Among other cost saving design points, it ate the existing Warwick southern bypass and ploughed under this roundabout, providing even more interchanging traffic and grade separation in the wrong direction (and indeed, for several years, traffic on the M40 underneath was probably lighter than that round the junction itself).

What would be better?

For a long time this page said that a flyover would be nice, but was unlikely. Well, sometimes dreams come true, and the flyover happened — though, unexpectedly, not neatly across the top of the roundabout as expected. It passes completely north of the existing junction and ends at another, new roundabout to the west. How odd. It has, however, fixed Longbridge Island for the forseeable future and so this poor junction gets a reprieve.


Right to reply

Annette 27 October 2006

As I live off J12 of the M40, work in both Birminghgam and Coventry, and my son goes to school in Stratford upon Avon, I find it almost impossible to avoid this junction, and it's becoming more hellish all the time. It gets gridlocked on a regular, if not yet frequent, basis, though the frequency of these situations is increasing noticeably.

One of the problems is the way the junction is used by drivers. If only they would stay out of the yellow boxes until their exit road is clear, then a lot of the more serious congestion could be avoided. Granted, they may have to sit still for a few changes of the lights, but they would get round in a reasonable time.

On three occasions recently, it has taken me over two hours to get from Stratford to the M40 south (with hindsight, I should know better and have taken the country route through Wellesbourne, though if Longbridge Island is OK, then it's marginally quicker for me to use the main roads) simply because of the gridlock on the roundabout.

And where are the police and the Highways Agency when this happens? Nowhere to be seen! Cameras should be installed on the roundabout and EVERYONE who enters a box when they shouldn't, should be nicked, fined and given three points. Hopefully, that would make them think about using this difficult junction in a more sensible and less selfish way.

Peter Davies 10 February 2007

The current plan includes not only running the A46 to the west, but also widening the main roundabout to 4 lanes and improving sliproads. Going north on A429 we get 12 seconds on the lights and we inexplicably lost our 3rd lane some years ago. With the Barford bypass there is some recognition that the A429 is a important road and this junction a bottleneck.

Alan Locke 10 October 2007

Improved recently by traffic lights, the island only really causes major headaches if approaching the South from the A46 in rush hour (you can queue all the way back to Warwick Parkway) or if there's an accident. Has a nasty habit to snarl up horrendously if there's so much as a shunt on the M40. Not bad I guess, but still one or two lanes that merge and lead to either party wagging fingers and hooting horns a-plenty.

Mark 8 January 2008

Having been involved in an accident on this roundabout recently I would draw peoples attention to the lane discipline on the section of the motorway between the A46 on the north side of the junction, the A429 to Warwick and the M40 South slip road.

At the point when you have gone past the A46 north exit and are waiting at the entry of the A46 south, might I remind drivers that both the inside lane (marked A429 & M40 S) and the next lane over (marked M40 S) go down the M40 south slip road. If you are not aware of this it looks for all the world that the left lane only goes to Warwick. Had the right side of my vehicle hit by a driver who came across into my lane and may not have realised the left lane also goes that way!

This appears to be a common problem specifically at that point. It doesn't help when impatient drivers coming from Warwick on the A429 straddle the yellow hatched box forcing you over into other lanes. I agree with a previous post, you should only enter these boxes if your exit the other side is clear. There should be cameras!

Matthew Ling 15 April 2008

Work has now started on the new flyover for the A46. Let's see how long before the new design makes it into Bad Junctions.

I notice from the Highways Agency pages on this project that the 'improvement' removes one roundabout from the mainline of the A46 and replaces it with another one! Admittedly it is smaller and will carry less traffic, but this smacks of cost-saving (again). Why not have a simple west-facing merge/diverge and use the same bridge to allow access to the B4463?

Dmitriy 18 May 2009

As a part of the joke, if you are going to Leamington Spa and come to A46 south of Kenilworth, the direction signs to Leamington lead you to this roundabout (instead of the shorter route to the north). As a result A46 south is queuing for miles in front of this roundabout during rush hour.

Andy Taylor 31 May 2009

Driving past recently, I noticed the huge quantity of earthworks required to split the southbound A46, but nothing similar on the northbound side. That prompted me to take a look at the plans on the Highways Agency website and there is a stupid little roundabout in the middle of the realigned A46. They have probably saved a few quid by not building a small bridge at the expense of bringing all the through traffic to a halt. The junction should have been built correctly with the A46 passing over the M40 in the first place.

Since then we have had months of roadworks to put traffic lights on the roundabout, followed a few years later by months of roadworks widening the roundabout. These were never going to fix the problem. Now when the current scheme has been finished it will still not be right, and the cost in both construction and delays will have been much higher than getting it right first time.

E.M. 25 November 2009

I would do anything to avoid this island,and always join the A46 Warwick bypass from the Hatton junction instead. I remember it before the M40 and the lights, and have only been on it three times since, on two occasions, unwillingly.

Rob 3 February 2010

Flyover for A46 through traffic (Stratford <-> Coventry) is now open, and has reduced dramatically the amount of traffic using the main island. The new small roundabout doesn't seem to be causing issues.

One thing that seems a little odd, is that heading south on the A46 towards the junction, the signs for M40(S) send you left to the main junction whilst those for M40(N) send you over the new flyover, then left, left and left again to join the motorway. Maybe this will seem more logical when the roundabout widening is complete (scheduled for mid this year).

Les 8 February 2010

The new bypass is now open, but fairly quiet.

I came south down the A46 onto the M40 North. You are signposted down the new road, over the motorway, left on a hellishly sharp sliproad missing the new island, then onto the main island, then first exit.

I guess this all saves you going all the way around the main island, but I would watch out on the news for the first lorry to fall over on the corner by the new small island.

Sam 27 April 2010

The traffic on the main island is reasonable now that the bypass has opened, even in rush hour. A huge problem is that a lot traffic uses the M40 between J15 and J14 during rush hour. This stretch is the only way past Warwick to the south - this bit of the M40 was the Warwick southern bypass (as mentioned).

In the morning, the hard shoulder from J15 to J14 is often a fourth lane of queuing traffic - joining the M40 at J15 to head to London requires one to get into the middle lane as soon as possible, dodging M40 traffic cutting over your slip road to join the hard shoulder queue. If you stay in the left lane you need to watch out for traffic trying to join the queue late on.

I can see the above only getting worse now that J15 has improved. I think the M40 needs to be 4 lanes between J15 and J14. No idea if there is any plans for this though.

blundelo 12 December 2011

Generally, the junction functions a lot better since the A46 bridge was opened. However, I exit the southbound M40 to take the A429 northbound into Warwick as part of my daily commute, and often see drivers completely baffled by the lane options available.

The main junction is still traffic-light controlled, but can be bypassed via a filter lane for traffic leaving the M40(S) to join the A46(N), which is obviously not light-controlled (it would be a bit pointless otherwise). However, I often see drivers pull into the filter lane only to stop at the red light, thinking it applies to them despite the lack of a stop line. I've never seen anyone plough straight into the back of a stationary vehicle there, but it's only a matter of time.

Now, on the slip road approaching the junction itself there are two lanes, the right-hand one of which then splits in two to make three lanes in total for the "roundabout". The obvious destination for the left-hand lane would be the A429(N), since the first exit from the roundabout, the A46(N), is already catered for by the aforementioned filter lane.

Obvious, but wrong.

The left-hand lane is also for the A46(N) only, although why anyone would want to wait at the lights to turn left rather than use the filter lane is beyond me. It may be the case that the planners thought that there would be enough traffic to justify having two lanes for A46(N) traffic, but if so, why not just build a two-lane filter - it's already wide enough, with one lane's worth of tarmac covered in hashmarks - and have just two lanes feeding into the roundabout? On the other hand, it may be that the planners feared a lorry might roll over on the filter lane, it is a fairly sharp turn given that it's under national speed limit, but this would seem an extreme case of contingency planning for something that you never want to happen - why not just allow the left-hand lane through the lights to be used for A46(N) traffic in those rare circumstances?

Then, the middle lane: this is for A429(N), no other option given that the left lane is for the A46(N), but this middle lane is also marked and signed for the A46(N), making two light-controlled lanes available for a route that already has a dedicated free-flowing filter lane! Bonkers!

Of course, what happens in practice is that drivers not totally familiar with the junction leave the motorway, see the filter lane for the A46(N) and logically assume that the next lane will be for the A429(N), ignoring the signs and road markings that state "COV ONLY" for the left-hand lane. This means that two lanes of traffic are now fighting for the one available lane on the roundabout with access to the A429(N) into Warwick.

The final (right-hand) lane is for traffic wishing to take both the A429(S) and A46(S). I never see any major issues with this (although I never go that way so wouldn't expect to); however I do frequently see drivers in the (pointless) left-hand lane at the lights cut right across my lane and into the A429(S)/A46(S) lane. Whether this is through confusion, or the belief that they own the road, I couldn't say.

Coming southbound out of Warwick towards the junction on the A429 and heading for the M40(N), the situation seems a lot clearer, the middle lane is the correct one, although the right-hand lane seems, by my observations, to be the M40 lane reserved for BMWs, Mercedes-Benzes, and anyone else whose sense of their own importance is inflated enough to enable them to behave in a fashion which, if they tried it in the Post Office on pension day, would earn them a walking frame to the shinbone.

Patricia Saville 4 April 2015

I hate this island no matter how careful I am I miss the A46 exit and end up going back on to the M40 ugh! It's the only island I have a problem with it just is not signed correctly or road marked correctly.

Andy Taylor 5 October 2017

This should be returned to bad junctions for teh same reasoning as the Almondsbury Interchange. J14 is way too close. At peak times, there is a queue on the hard shoulder to leave the M40 at J14. Quite regularly this extends back up the hard shoulder of the slip road to join the M40 from this junction.

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