M2 junction 5 improvements

[AnOrdinarySABREUser]

7 months for drainage and barrier repairs though. Despite the length of TM, the works area seems to be roughly two miles in length starting around a mile west of Junction 6 by Brogdale and ending just as you go round the bend after climbing up out of the Doddington valley at Newnham. Maybe it's a concrete barrier they're installing and installing crash cushion terminals on the verge barriers. Most of the central barrier and drainage dates from when the road was rebuilt in the early 90's

I suspected that they were installing a concrete barrier too. This would justify the longevity of the works, however, I doubt this as National Highways installed new steel barriers at J5 of the M2. We'll have to see in a few months time for ourselves.

Traffic on the A2 between Sittingbourne and Faversham is worse than ever, with more people wanting to avoid the roadworks despite there being virtually no difference in journey times on the M2. It isn't as if the M2 is fast-moving at peak times anyway. So pointless.

On a more fanciful note, this would've been a good opportunity to smartify the M2 and widen it to three lanes in each direction with all lane running or an intermittent hard shoulder. Despite this, traffic flow on the M2 between J4 and J7 is fairly good due to the long gaps between each junction, though it could be better.

[Ritchie333]

I did a gig in Kemsley on the weekend. I normally go to Sittingbourne via the A251 and A2, but in this instance I went M20 / A249. There were no problems at junction 5, and I pretty much sailed through. The works are progressing nicely, with the central part of the flyover left to fill in.

[AnOrdinarySABREUser]

I did a gig in Kemsley on the weekend. I normally go to Sittingbourne via the A251 and A2, but in this instance I went M20 / A249. There were no problems at junction 5, and I pretty much sailed through. The works are progressing nicely, with the central part of the flyover left to fill in.

After the flyover is opened to traffic, the main issue that needs to be addressed ASAP is the alignment of and at-grade right turns on the A249 between Stockbury and Maidstone. This is not the standard expected of a road carrying 43,778 vehicles a day on average. For reference, the recently dualled A556 by Manchester carries 43,360 vehicles on average.

[Brenley Corner]

Traffic on the A2 between Sittingbourne and Faversham is worse than ever, with more people wanting to avoid the roadworks despite there being virtually no difference in journey times on the M2. It isn't as if the M2 is fast-moving at peak times anyway. So pointless.

I must admit that I was dreading these works going in when I first saw the advance notice signs at the end of last year, but so far my concerns have been unfounded.

I use the M2 between J5 and J7 each way in the rush hour twice a week and have found that it has been flowing more evenly since the road works went in and my journey times haven't changed. It used to be more 'surge and slow' and the belief that there are average speed cameras (to my knowledge there aren't any - with just a 50mph limit and "Police. Speed Check Area" signs doing the job) has actually helped peak flows. Mind you, it feels really narrow through the TM and personally I wouldn't want to be doing more than 50 anyway.

[Peter Freeman]

It's good to see this project on the home straight. However, it's taken much time, disruption and expense (>150M UKP?), simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent. Six-ramp Parclo? Perhaps next time!

[Brenley Corner]

It's good to see this project on the home straight. However, it's taken much time, disruption and expense (>150M UKP?), simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent. Six-ramp Parclo? Perhaps next time!

Unfortunately the topography of the junction precludes many completely free flow solutions without vast amounts of money being spent - the A249 travels along the floor of a deep narrow valley and the M2 crosses the valley on a huge 1960s viaduct; the grade separation having been achieved “naturally” since day 1.

So far as I’m aware the scheme is around £100m and as a side note, the roundabout is planned to be unsignalised once complete so far I know; the current signals only staying in place until scheme completion.

[Fluid Dynamics]

It's good to see this project on the home straight. However, it's taken much time, disruption and expense (>150M UKP?), simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent. Six-ramp Parclo? Perhaps next time!

It a good scheme and much better than a stackabout. It actually provides free flow links in 3 directions between the M2 and A249 so reduces significant the traffic on the roundabout, and as Brenley Corner states the traffic lights are due to be removed. Looking at key flows the only real admission in my view, as someone who uses the junction every few months, was an M2 westbound to A249 Southbound flow as M25 West and South traffic is directed to use that route. One of the potential impacts of the scheme in removing the roundabout, is whether it places more pressure on M20 J7?

[AnOrdinarySABREUser]

I must admit that I was dreading these works going in when I first saw the advance notice signs at the end of last year, but so far my concerns have been unfounded.

I use the M2 between J5 and J7 each way in the rush hour twice a week and have found that it has been flowing more evenly since the road works went in and my journey times haven't changed. It used to be more 'surge and slow' and the belief that there are average speed cameras (to my knowledge there aren't any - with just a 50mph limit and "Police. Speed Check Area" signs doing the job) has actually helped peak flows. Mind you, it feels really narrow through the TM and personally I wouldn't want to be doing more than 50 anyway.

Same here. It goes to show that the main reason why smart motorways are congested (other than the traffic levels and stranded vehicles) is that not many people observe the variable speed limit and lane closures signed overhead.

I'll concede that some smart motorways have their limits dropped for seemingly inexplicable reasons, such as reported "debris" on the road which is no where to be seen by the driver, however, for National Highways to confirm these reports, they'd have to put up Orwellian levels of surveillance along the smart motorway in question which is unfeasible. It isn't a good enough excuse to ignore signage. The impression that the police are monitoring traffic speeds on the motorway are a factor which contributes to compliance.

It's good to see this project on the home straight. However, it's taken much time, disruption and expense (>150M UKP?), simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent. Six-ramp Parclo? Perhaps next time!

IIRC, the final cost of the scheme was £92m, which mostly came from the retaining walls and bridges (2 at the roundabout, 1 on the A249 SB exit).

Personally, I think that this is the best solution out of all the options presented. This solution makes of the major movements (mostly right turns) freeflow bar the M2(W) to A249(S) movement. This movement was included in the TAR stage alongside a dumbbell variant (see jackal's post here) but these bells and whistles were ultimately removed to bring the cost down to a justifiable level. Also note that the M2(E) slip roads have a noticeably worse alignment with a much tighter turning radius than the preferred option.

A fancy six-ramp parclo is unsuitable at Stockbury because of the complexity and topography. If the traffic levels on the A249 were lower then this could be justified as an at-grade solution. However, as a grade-separated solution, the additional complexity is simply unnecessary. The preferred option handles all of the major movements very well and only one as I've mentioned above has to go through the roundabout, and then again there'll be minimal traffic on it.

[Ben302]

So far as I’m aware the scheme is around £100m and as a side note, the roundabout is planned to be unsignalised once complete so far I know; the current signals only staying in place until scheme completion.

It would be interesting how the London bound exit slip copes without the signals unless they are planning on making it 3 lanes on the approach to the roundabout as was originally there before the works started. I imagine a fair few people will use the Oad Street and LAR which will plug into the roundabout inbetween it and the Southbound A249 on ramp. I imagine queues will form along the Oad street link as there will probably be a steady flow of traffic going from the Westbound exit down the hill and on to the roundabout. Gaps in this movement flow will probably be very few at busy periods. Even with the removal traffic not intending to use the M2 via the flyover, a fair chunk will still use the roundabout to head to and from the M2 and beyond. I guess that'll be answered once the flyover is finished and open, judging by the progress in the past month, seems not too far off.

[Peter Freeman]

It's good to see this project on the home straight. However, it's taken much time, disruption and expense (>150M UKP?), simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent. Six-ramp Parclo? Perhaps next time!

Unfortunately the topography of the junction precludes many completely free flow solutions ...

Some, not all. Anyway, my preferred upgrade would have remained 2-level, and not completely free-flow. Does the population of Sittingbourne and the Isle of Sheppey really warrant a full motorway?

... without vast amounts of money being spent - the A249 travels along the floor of a deep narrow valley and the M2 crosses the valley on a huge 1960s viaduct; the grade separation having been achieved “naturally” since day 1.

I followed this topic from the start, and I appreciate the influence of the topography. A nuisance, yes, and difficult to absorb.

So far as I’m aware the scheme is around £100m and as a side note, the roundabout is planned to be unsignalised once complete so far I know; the current signals only staying in place until scheme completion.

I stand corrected. But virtually all uk stackabouts were initially unsignalised. It's only a matter of time.

[Darren]

Some, not all. Anyway, my preferred upgrade would have remained 2-level, and not completely free-flow. Does the population of Sittingbourne and the Isle of Sheppey really warrant a full motorway?

Having lived on the Isle of Sheppey for 40 years, since I was a toddler, I've watched as countless fields, and several orchards, have vanished under masses of housing, both on Sheppey and the Iwade/Sittingbourne area. I've also seen how the caravans and chalets of eastern Sheppey have gone from being almost entirely holiday-based to providing a large amount of cheap housing, which doesn't appear on the stats. (The reason is the parks are officially 8 to 10 months occupancy, but increasingly people live in them throughout that period - they have to provide a "home address" elsewhere, but it's usual just to put a relative or friend down. The local message boards are full of people looking for alternate accommodation in the two month closed period each year).

The population of Sheppey, Sittingbourne, Iwade, Newington and Bapchild is now over 100,000, and that doesn't take into account the holidaymakers/long-stayers in the holiday parks on the Isle. Sheerness is a busy port, and there are now two regional distribution centres (for Aldi and Morrisons) accessed off the A249. And the prisons at Eastchurch lead to a lot of to-ing and fro-ing as well, with a large chunk of the staff there coming from the mainland each day.

There are thousands more houses in the pipeline in the next decade, and doubtless there will be even more beyond that.

All this means that the upgrade to J5 of the M2 was well overdue, and the more free-flowing the interchange the better. I'm surprised TBH that there isn't more of a push to widen the M2 itself, as areas further east (Canterbury, Thanet) have also seen mass building going on.

[jackal]

It's good to see this project on the home straight. However, it's taken much time, disruption and expense (>150M UKP?), simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent. Six-ramp Parclo? Perhaps next time!

Despite my enthusiasm for 6 ramp parclos, the solution being built is much better at this quirky site. The key point is that it leaves the seven busiest movements freeflowed, which are in order (12 hour flows):

1. M2 to M2 no.1 (N/A)
2. M2 to M2 no.2 (N/A)
3. M2eb to A249nb (11.5k)
4. A249nb to A249nb (10.3k)
5. A249sb to M2wb (9.6k)
6. A249sb to A249sb (8.5k)
7. A249nb to M2eb (7.2k)

The only somewhat busy movement it leaves non-freeflow is number 8, M2wb to A249sb (6.5k). All the remaining movements are below 2.2k. M2wb to A249sb delays should be minimal given it's essentially a left turn at an unsignalised rbt that handles no other significant flows.

By contrast a 6RP would make movements nos 4 and 6 (i.e., the A249 mainline) non-freeflow. It does not gain any freeflow - M2wb to A249sb still has to stop at an at-grade junction for the local road (unless you're proposing the cost of a new GSJ elsewhere). It would be a very significant loss of freeflow and capacity compared to the design being built.

The selected design diverges from a regular stackabout by having two freeflow right turns, due to the slips being folded, which is unusual at a stackabout. Furthermore, these are by far the two busiest right turns (A249sb to M2wb and
A249nb to M2eb).

With those two freeflow rights it really isn't comparable to a regular stackabout like Wisley or Simister, where all the right turns fight around the rbt. It's arguably even higher capacity than stackabouts with one freeflow right turn like Lofthouse or Tarbock - at the least it's comparable. Compared to these it does have some more convoluted left turns, but only for less busy movements.

In short, it's pretty outrageous bang-for-buck in UK roadbuilding terms, roughly equivalent to a four-level junction like Lofthouse, but for less than £100m.

PS - Here's the data. The strange junction configuration means it must be read with care (some left turn arrows are for right turns).

[Peter Freeman]

Jackal, your post dropped in just ahead of mine! I agree with it. The HE end result is good (though possibly not the best - would you do that now, from a blank sheet?).

I submit my final post unaltered anyway, and will close.

... simply to convert a 2-level 2-bridge GSR equivalent into a 3-level signalised stackabout equivalent ...

It a good scheme and much better than a stackabout.

It is quite a good scheme, and cost less than I thought. The new layout will last, in capacity terms, for many years - perhaps forever (the previous one, with minor tweaks, lasted for forty).

However, it is a stackabout.There are two straight-though freeflow motorways, occupying two levels. The third level joins those together via a roundabout. The two motorways have eight ramps in total. By that basic definition, it's a stackabout.

Fortunately, it has, like some normal-shaped stackabouts, separated left turns, which help a lot. The unusual things about it are -
1. The roundabout is displaced into the valley, and
2. Some ramps are folded into trumpet shapes, generating parclo-like loops.

Some right turns are swapped for lefts, and left turns swapped for rights, by the folding - mainly, as luck would have it, beneficially.

This has been a long thread, and numerous alternatives, some good, from HE and from Sabre, were discussed. Most of my points have been covered in previous pages, so ...

[jackal]

Jackal, your post dropped in just ahead of mine! I agree with it. The HE end result is good (though possibly not the best - would you do that now, from a blank sheet?).

There was an opportunity for a full freeflow junction here using only two new bridges. I posted my sketch of this earlier in the thread.

On some level it's disappointing that such an opportunity was not taken. But though it had no more bridges than the proposed design, it would have been quite a lot more expensive as there would be extra sliproads, substantial earthworks given the topography, and alternative local access arrangements. Can I, hand on heart, say an extra £50m-£100m would be justified when the top 7 movements are already freeflow? No, I can't. So to me the scheme is that rarest of things - a 10/10 NH design.

The best complaint is really with the reserve gap remaining at Church Hill. But this is outside the scheme extent and would have blown the budget if included, probably downgrading the heart of the scheme to a hamburger or similar. That would be a terrible trade.

So I'd say that's more a complaint with the wider A249. As others have mentioned, this is one of several gaps on the A249 that should be filled in with a follow-on scheme. The current scheme would fit well with that. A bridge near Church Hill would allow Stockbury village traffic to access the roundabout via the new LAR.

General arrangement: https://s3.eu-west-2.amazonaws.com/asse ... rawing.pdf

[Brenley Corner]

So I'd say that's more a complaint with the wider A249. As others have mentioned, this is one of several gaps on the A249 that should be filled in with a follow-on scheme. The current scheme would fit well with that. A bridge near Church Hill would allow Stockbury village traffic to access the roundabout via the new LAR.

In an ideal world the follow-on schemes would be great, but the A249 south of Stockbury is a local authority road rather than National Highways and, given the state of Kent County Council finances, that is unlikely to happen this century!

=========

This morning the project announced that they would be closing the A249 south from Stockbury roundabout for around 5 weeks from 23rd February, along with the M2 WB off-slip. I totally understand the reasons and the need for the closure. My concern is with the diversion route which is the M2 towards J3 and then down to the M20 along the A229, plus with M2 WB to A249 NB traffic having to detour via M2 J4 to return to J5. I have written to the project office with my concern that:
1) You have at least 4 lanes of traffic on a 2 lane motorway
2) You have all A249 SB traffic trying to merge onto the M2 WB at J5
I can see that this is going to leave the M2 WB stationary most of the day possibly tailing back towards J6, plus the gridlock in the locality where traffic rat-runs. Ideally they need to impose a temporary limit on the M2 WB between J5 & J4, control access WB at J5, and cannot temporary hard shoulder running be creating using TM to provide extra capacity?

[AnOrdinarySABREUser]

This morning the project announced that they would be closing the A249 south from Stockbury roundabout for around 5 weeks from 23rd February, along with the M2 WB off-slip. I totally understand the reasons and the need for the closure. My concern is with the diversion route which is the M2 towards J3 and then down to the M20 along the A229, plus with M2 WB to A249 NB traffic having to detour via M2 J4 to return to J5. I have written to the project office with my concern that:
1) You have at least 4 lanes of traffic on a 2 lane motorway
2) You have all A249 SB traffic trying to merge onto the M2 WB at J5
I can see that this is going to leave the M2 WB stationary most of the day possibly tailing back towards J6, plus the gridlock in the locality where traffic rat-runs. Ideally they need to impose a temporary limit on the M2 WB between J5 & J4, control access WB at J5, and cannot temporary hard shoulder running be creating using TM to provide extra capacity?

Why can't they contraflow the A249 between the roundabout and reservation gap while they finish the flyover? They could open the A249(E) onslip and alternate between that and the A249(W) offslip during this. I know that the space here is tight between the slips and the roundabout but there's apt room for it in the interim.

[Davethegasman]

Traffic on the A2 between Sittingbourne and Faversham is worse than ever, with more people wanting to avoid the roadworks despite there being virtually no difference in journey times on the M2. It isn't as if the M2 is fast-moving at peak times anyway. So pointless.

I must admit that I was dreading these works going in when I first saw the advance notice signs at the end of last year, but so far my concerns have been unfounded.

I use the M2 between J5 and J7 each way in the rush hour twice a week and have found that it has been flowing more evenly since the road works went in and my journey times haven't changed. It used to be more 'surge and slow' and the belief that there are average speed cameras (to my knowledge there aren't any - with just a 50mph limit and "Police. Speed Check Area" signs doing the job) has actually helped peak flows. Mind you, it feels really narrow through the TM and personally I wouldn't want to be doing more than 50 anyway.

Hi all. I use the M2 daily. I haven't noticed cameras here before but I have today. I'm 95 percent sure. The lanes are so tight I've been focusing on where I'm driving but I'm sure I see average speed cameras in the central area today. They look different but definitely 2 facing each way on multiple parts along this route.

I'll be honest I've sped through here over 50 for the last week and this week so hoping they're not active.

Anyone else seen cameras here? I'll be back down there Monday so I'll look again and update if no1 has by then

[Ben302]

This morning the project announced that they would be closing the A249 south from Stockbury roundabout for around 5 weeks from 23rd February, along with the M2 WB off-slip. I totally understand the reasons and the need for the closure. My concern is with the diversion route which is the M2 towards J3 and then down to the M20 along the A229, plus with M2 WB to A249 NB traffic having to detour via M2 J4 to return to J5. I have written to the project office with my concern that:
1) You have at least 4 lanes of traffic on a 2 lane motorway
2) You have all A249 SB traffic trying to merge onto the M2 WB at J5
I can see that this is going to leave the M2 WB stationary most of the day possibly tailing back towards J6, plus the gridlock in the locality where traffic rat-runs. Ideally they need to impose a temporary limit on the M2 WB between J5 & J4, control access WB at J5, and cannot temporary hard shoulder running be creating using TM to provide extra capacity?

Why can't they contraflow the A249 between the roundabout and reservation gap while they finish the flyover? They could open the A249(E) onslip and alternate between that and the A249(W) offslip during this. I know that the space here is tight between the slips and the roundabout but there's apt room for it in the interim.

Agreed there is room there to construct a small bit of temporary tarmac and re-mark the road as a temporary S2 contraflow and utilise the church hill crossover as a switch back onto the main carriageway. Or get the A249 southbound carriageway constructed and trafficked with a temporary tie in to the existing road at Church lane then close it over a couple of weekend or overnight to construct the permanent and final tie-ins at Church Hill

[Brenley Corner]

This morning the project announced that they would be closing the A249 south from Stockbury roundabout for around 5 weeks from 23rd February, along with the M2 WB off-slip. I totally understand the reasons and the need for the closure. My concern is with the diversion route which is the M2 towards J3 and then down to the M20 along the A229, plus with M2 WB to A249 NB traffic having to detour via M2 J4 to return to J5. I have written to the project office with my concern that:
1) You have at least 4 lanes of traffic on a 2 lane motorway
2) You have all A249 SB traffic trying to merge onto the M2 WB at J5
I can see that this is going to leave the M2 WB stationary most of the day possibly tailing back towards J6, plus the gridlock in the locality where traffic rat-runs. Ideally they need to impose a temporary limit on the M2 WB between J5 & J4, control access WB at J5, and cannot temporary hard shoulder running be creating using TM to provide extra capacity?

I wrote to the project office e-mail address on 2nd February expressing my concerns especially about the M2 capacity (i.e the equivalent of 4 lanes of traffic - 2 x M2, 2 x displaced A249) trying to use the 2 lane M2 Londonbound.
I received their reply this morning:

Dear <snip>

Thank you for your email on 02 February regarding the M2 junction 5 improvements scheme.

Following your email regarding the traffic capacity of the M2, we reviewed the plans and discussed with KCC and our colleagues in National Highways Operations Department. All parties are content with the current plans to divert traffic onto the M2. We will monitor the traffic flows when the closure is implemented and re-assess if required.

Thank you again for contacting us, if you have any further queries in relation to this scheme, please feel free to contact us again at m2j5@nationalhighways.co.uk
    
Kind regards

<snip>
Project Manager
M2 Junction 5 Improvements
Regional Investment Programme South East

[Darren]

The A249 south of the roundabout has now closed for five weeks, as the project moves onto the next phase. The Maidstone-bound traffic is directed along the A2 or M2 west, then it's meant to use the Bluebell Hill junction. Anecdotally there have been problems in the country lanes east of the A249, with locals trying to instead bypass the closure and rejoin the A249 further south. This has, predictably, led to gridlock - all it takes is a couple of people, maybe one in a large Transit, meeting each other, then the whole thing gums up. Reversing is something people don't want to do, or even can't (if traffic starts building up).

During the closure the new southbound alignment will be tied in with the existing A249 (so you'll leave the roundabout, southbound, on the new slip road), and the current southbound carriageway will, in effect, become a local access road for those unfortunate properties which front the A249.

Some more drone photos have been posted to the local A249 Facebook group, I've included a selection below.

EDIT: A mod told me to delete the photos as I don't have permission to post them.

You can see them here:

https://www.facebook.com/groups/2473389 ... 567632880/