M2 junction 5 improvements

[Brenley Corner]

Local newspaper article: "New drone photos show A249 flyover works taking shape at M2 junction 5 Stockbury roundabout"

Looking at these images, I didn't realise up to now how much the A249 immediately south of the roundabout will end up realigned.

Tony

[Fluid Dynamics]

Local newspaper article: "New drone photos show A249 flyover works taking shape at M2 junction 5 Stockbury roundabout"

Looking at these images, I didn't realise up to now how much the A249 immediately south of the roundabout will end up realigned.

Tony

Yes I entirely agree. The road is moving quite a way to the west that wasn't immediately evident from the plans, no doubt to allow the local access road to be constructed. I hadn't understood why so much work needed to be done to the coastbound slip road which has facilitated a significant closure, but those pictures tell the story. This is causing misery to some work colleagues.

[jackal]

Seeing those extra spans under the M2 I can't help but feel aggrieved that they're not being put to use:

[Fluid Dynamics]

Seeing those extra spans under the M2 I can't help but feel aggrieved that they're not being put to use:

M2 A249 crop - Copy.png

That would be nice, but in the end this scheme is much better than say M25 J10.

The major flow that they aren't addressing/free flowing by this scheme, albeit by removing traffic from the roundabout, is M2 westbound to A249 Southbound. The local access road means here is no free flow slip for that direction. I seem to recall one of the dropped options addressed this. One of the options also had an M2 Eastbound to A249 Northbound slip road arrangment like yours.

The strange layout of the M2 junction, where on the A249 you turn west to go east northbound, and the opposite westbound, means that major flows such as A249 North to M2 East already were already free flow.

The other strange point about this junction is that signs on the M2 westbound approach to Junction 5 direct traffic towards the A249 for the M20 and M25 westbound, whereas the A249 at junction M20 J7 is just signed as Sheppey.

[Brenley Corner]

The major flow that they aren't addressing/free flowing by this scheme, albeit by removing traffic from the roundabout, is M2 westbound to A249 Southbound. The local access road means here is no free flow slip for that direction. I seem to recall one of the dropped options addressed this. One of the options also had an M2 Eastbound to A249 Northbound slip road arrangement like yours.

The strange layout of the M2 junction, where on the A249 you turn west to go east northbound, and the opposite westbound, means that major flows such as A249 North to M2 East already were already free flow.

The other strange point about this junction is that signs on the M2 westbound approach to Junction 5 direct traffic towards the A249 for the M20 and M25 westbound, whereas the A249 at junction M20 J7 is just signed as Sheppey.

I can see your points that you make here.

The M2 WB to A249 SB is a fairly major flow but rarely causes tailbacks so I can see why they have omitted it in favour of a relocated local access.

The A249 SB approaching Stockbury roundabout has queues every morning and evening rush often stretching back 1 or 2 miles so I can see why they have removed the local access road from that corner of the roundabout in favour of a free-flow slip road from A249 SB to M2 WB. That, combined with the flyover, should alleviate a lot of those queues. M2 EB to A249 NB is also being added as free-flow to match as the traffic flows between A249 North and M2 West are consistently high in each direction.

The M20 exit signing at J7 EB is bizarre with the exit only being signed as A249 Sheerness (not even Canterbury). My theory is that it is a National Highways attempt to keep port traffic on the M20 by avoiding any mention of the A2 / M2 and destinations thereon. Before the J7 exit was reconfigured in recent years, the signs also gave Canterbury and Ramsgate as destinations so their removal seems to have been a conscious decision.

[jackal]

M2 EB to A249 NB is also being added as free-flow

That movement is already freeflow and there will be no real change for it. As discussed below a rejected option made it more direct, which is perhaps what you have in mind.

M2 A249 crop - Copy.png

That would be nice, but in the end this scheme is much better than say M25 J10.

The major flow that they aren't addressing/free flowing by this scheme, albeit by removing traffic from the roundabout, is M2 westbound to A249 Southbound. The local access road means here is no free flow slip for that direction. I seem to recall one of the dropped options addressed this. One of the options also had an M2 Eastbound to A249 Northbound slip road arrangment like yours.

The strange layout of the M2 junction, where on the A249 you turn west to go east northbound, and the opposite westbound, means that major flows such as A249 North to M2 East already were already free flow.

The other strange point about this junction is that signs on the M2 westbound approach to Junction 5 direct traffic towards the A249 for the M20 and M25 westbound, whereas the A249 at junction M20 J7 is just signed as Sheppey.

I agree, it's a good scheme. And it does have advantages over my design, being cheaper and accommodating the local traffic. It's a 9/10, but it still niggles that it's a unique site where full free flow wouldn't cost that much more.

Your recollection about rejected options is pretty much right though it was actually a single option (option 4) with the two features of freeflow for M2 Wb to A249 Sb and direct M2 Eb to A249 Nb.

Not worthwhile IMO - if you're doing that scale of work you might as well do the full freeflow (which has only two bridges) and put a bridge somewhere else for a local junction. The option being built is a cost effective alternative.

[Brenley Corner]

M2 EB to A249 NB is also being added as free-flow

That movement is already freeflow and there will be no real change for it. As discussed below a rejected option made it more direct, which is perhaps what you have in mind.

Yes, you're right - my mistake. However up to the point of closure of that slip road a couple of weeks ago, it was only a painted free-flow IIRC and felt dangerous especially if, for example, a lorry was using the free-flow and you were on the adjacent roundabout. In the new configuration it will be physically segregated.

[jackal]

M2 EB to A249 NB is also being added as free-flow

That movement is already freeflow and there will be no real change for it. As discussed below a rejected option made it more direct, which is perhaps what you have in mind.

Yes, you're right - my mistake. However up to the point of closure of that slip road a couple of weeks ago, it was only a painted free-flow IIRC and felt dangerous especially if, for example, a lorry was using the free-flow and you were on the adjacent roundabout. In the new configuration it will be physically segregated.

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

[Darren]

Another update with lots of "in progress" photos from KentOnline:

https://www.kentonline.co.uk/sittingbou ... te-276629/

[Ben302]

Interesting read. Since the photos were taken, the "flat pack" bridge has had it's parapets installed and the southbound off slip has progressed to the point that some concrete sub-surfacing has been put down in the area where the v channel drains have been constructed (the existing A249 in the area is slipform rigid concrete pavement). The M2 coastbound slip road works seem to be progressing well with the road bed and layout becoming more obvious, with kerb lines now being laid. I think the aim is to get the slip roads constructed and open first before the main flyover works can start, which is planned for mid 2023.

[Ben302]

Update on this:

It was announced yesterday that the reopening of the M2 J5 coastbound slips has been put back by 10 days to Monday January 23rd along with weekend closures post Christmas shutdown which are going to see the Northbound A249 closed every weekend until mid March.

Progress had been hampered by the recent snowfall meaning the final surfacing of the new sliproads and western extremities of the enlarged Stockbury roundabout has yet to be done. Elsewhere the sliproads (surfacing aside) look ready to go with surfacing barriers and landscaping all but done, the rest of the area has seen small progression with drainage foundations and landscaping progressing. The next activities I imagine once the slip roads to and from the M2 open will be building the northbound on slip to the A249 as the southbound exit is just awaiting its surfacing and the approaches to the flatpack bridge are nearly there.

[AnOrdinarySABREUser]

On a recent trip to Chatham, I noticed that there seemed to be new Armco crash barriers on the M2 coastbound slip roads in the central reservation. Nothing particular major, but I found it quite odd considering that NH's recent approach to central reservation crash barriers are to install concrete barriers rather than Armco ones.

Does anyone know why NH would make that choice? I think it might have something to do with the tightness of the slip road, but I'm not too sure personally.

[Ben302]

On a recent trip to Chatham, I noticed that there seemed to be new Armco crash barriers on the M2 coastbound slip roads in the central reservation. Nothing particular major, but I found it quite odd considering that NH's recent approach to central reservation crash barriers are to install concrete barriers rather than Armco ones.

Does anyone know why NH would make that choice? I think it might have something to do with the tightness of the slip road, but I'm not too sure personally.

I think it's due to the approach to the roundabout being tightened and shortened. The sliproads have already been shortened once before when the A249 was upgraded in the mid 90's, the current scheme will make the roundabout even bigger still so they''ve had to excavate the bank to move the slip road mainline further back so that a less tight approach could be built, this should be done and open on the 23rd apparently. Also I think, given that the realigned portion of the reconstructed slip road is less than a couple of hundred yards long, it would mean that you'd have the concrete barrier start on the downhill part of the slip then curve round sharply, I think that the current layout with the lower box section to stop bikes sliding under will cope just fine

[Ritchie333]

I really should know more about what's going on with these works than I do, as it's not far away from me. However, it is possible for me to take alternative routes, heading up the A251 or A229 instead, so I can avoid it like the plague. I know it's causing problems for people living around Sittingbourne, who have to take the A2 through Teynham and Ospringe, and the number of HGVs along this section of the road has definitely increased.

[A303Chris]

The biggest thing following the completion of these works is will the A249 be trunked between the M20 and m2, it is only trunked north of the junction.

It seems bizarre that the M20 and M25, The West are signed from the M2 and A249 down the A249 to Maidstone, but it remains a county road.

[Ritchie333]

It seems bizarre that the M20 and M25, The West are signed from the M2 and A249 down the A249 to Maidstone, but it remains a county road.

I think the reason is that Detling Hill can't really cope with lots of HGVs. Going southbound (the original alignment), it's one of the few places where I think the speed limit on a primary dual carriageway is actually too high and you don't want to be doing more than about 40 on the bends. In poor weather, I can easily picture a nasty accident involving two 44 tonners elephant racing, or simply one approaching a bend at too high a speed. So I think it's best to send major goods traffic up the M2 / A2 / M25 instead, where the entire road is engineered to modern standards, instead of just tacked into an ancient coaching route.

[Brenley Corner]

The biggest thing following the completion of these works is will the A249 be trunked between the M20 and m2, it is only trunked north of the junction.

That seems to have crept under the radar. Excuse my ignorance but I assume that means National Highways will be responsible for its maintenance from that point onwards? What practical differences, if any, would be seen on the ground?

[frediculous_biggs]

The biggest thing following the completion of these works is will the A249 be trunked between the M20 and m2, it is only trunked north of the junction.

That seems to have crept under the radar. Excuse my ignorance but I assume that means National Highways will be responsible for its maintenance from that point onwards? What practical differences, if any, would be seen on the ground?

I think A303Chris was posing that as a question, rather than a statement

[Ben302]

The biggest thing following the completion of these works is will the A249 be trunked between the M20 and m2, it is only trunked north of the junction.

That seems to have crept under the radar. Excuse my ignorance but I assume that means National Highways will be responsible for its maintenance from that point onwards? What practical differences, if any, would be seen on the ground?

I imagine the TRO will end at the point the southern slips start and end and the upgraded Oad Street and diverted Maidstone Road will be handed back to KCC.

[Brenley Corner]

I think A303Chris was posing that as a question, rather than a statement

Yep, that was me not reading things carefully. D'oh!

I've since read the scheme page on National Highways and the trunk road will be extended - but only to the extent of the scheme as stated in the previous post. I think the A249 only retained trunk status to the north of the M2 is because of access to Sheerness port?