A3/M25 Wisley Upgrade
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A3/M25 Wisley Upgrade
The government plans to make the A3/M25 Wisley interchange one with free flowing links, as part of its new 'investment plan', over the next five years.
I was wondering how engineers would actually go about it. Would they use the existing roundabout in a new way and adapt it? Or would they create completely new structures and then remove the roundabout?
Either way it sounds like a big undertaking.
Alex
- hoagy_ytfc
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Re: A3/M25 Wisley Upgrade
I don't suppose they mentioned the M31 in this?mapalex wrote:The government plans to make the A3/M25 Wisley interchange one with free flowing links, as part of its new 'investment plan', over the next five years.
Nah, didn't think so! Shame...
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Re: A3/M25 Wisley Upgrade
The wording does suggest the plan is (was?) to replace the roundabout although what with I don't know. The junction is also complicated by a LILO on the A3 southbound on-slip, which I'm guessing would be closed?
While looking in the document I also noticed a mention of improving the A3 Guildford bypass between the A320 (where the current lane drop is) and the A31 under "schemes developed for the next road period" (whatever that means?). While widening that stretch to three lanes would be great, it would be expensive as there's a lot of structures that would need rebuilding, so I don't know how realistic that is. Even just increasing the length of some of the sliproad merges and diverges would help though!
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Re: A3/M25 Wisley Upgrade
When I opened this thread I was expecting it to be eleven months of work to build four left-turn filter lanes. Having read your detail I'm now convinced.Rubberduck wrote:I've found the document - the exact wording is "improvement of the Wisley interchange to allow free-flowing movement in all directions, together with improvements to the neighbouring Painshill interchange on the A3 to improve safety and congestion across the two sites".
The wording does suggest the plan is (was?) to replace the roundabout although what with I don't know.
That may well help - I sometimes travel on the A3 northbound in the morning peak and am impacted by a long queue to leave here. Problem is the capacity in this area is restricted by the low capacity of the M25 either side, of Guildford to the south, and of the urban area to the north.
- crowntown100
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Re: A3/M25 Wisley Upgrade
Can I point you towards the Road Investment Strategy and Road Period 1? The Coalition Government announced last year that they were creating 'Road Periods' to enable funding to be ready for new road projects long in advanced, meaning more schemes will be progressed to construction. Each Period is 5 years long and in this period they are planning on spending £15bn on the network. Any schemes that say they are being 'developed for the next road period' are exactly that. We should see construction on those routes start in the early half of Road Period 2 (2020-2025). That's the plan anyway. The current government show no sign of giving up on this plan.Rubberduck wrote:I've found the document - the exact wording is "improvement of the Wisley interchange to allow free-flowing movement in all directions, together with improvements to the neighbouring Painshill interchange on the A3 to improve safety and congestion across the two sites". Widening the M25 to 4 lanes through junctions between J10 and J12 is also mentioned. Both are in the "committed schemes" section - although the entire document has a disclaimer that it was published under the previous government (so I wouldn't hold my breath waiting for the diggers to arrive).
The wording does suggest the plan is (was?) to replace the roundabout although what with I don't know. The junction is also complicated by a LILO on the A3 southbound on-slip, which I'm guessing would be closed?
While looking in the document I also noticed a mention of improving the A3 Guildford bypass between the A320 (where the current lane drop is) and the A31 under "schemes developed for the next road period" (whatever that means?). While widening that stretch to three lanes would be great, it would be expensive as there's a lot of structures that would need rebuilding, so I don't know how realistic that is. Even just increasing the length of some of the sliproad merges and diverges would help though!
From the SABRE Wiki: Road Investment Strategy :
The Road Investment Strategy is a plan implemented by the Conservative/Liberal Democrat Coalition Government of 2010-2015 to provide more regular funding for the Strategic Road Network (SRN), or Trunk Roads, of England. The plan included turning the Highways Agency into a Government owned company called Highways England and providing fixed funding periods, or 'Road Periods', to allow more schemes to reach construction. As part of the first Road Period, the government committed
Re: A3/M25 Wisley Upgrade
How would that deliver "free-flowing movement in all directions"? I'm curious to understand the plan for this junction. It seems like an extraordinary commitment to transform a stackabout into a genuinely free flowing design such as a whirlpool.Johnathan404 wrote:When I opened this thread I was expecting it to be eleven months of work to build four left-turn filter lanes. Having read your detail I'm now convinced.Rubberduck wrote:I've found the document - the exact wording is "improvement of the Wisley interchange to allow free-flowing movement in all directions, together with improvements to the neighbouring Painshill interchange on the A3 to improve safety and congestion across the two sites".
The wording does suggest the plan is (was?) to replace the roundabout although what with I don't know.
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Re: A3/M25 Wisley Upgrade
Am I right in thinking M62/A1(M) was the most recent four-way full GSJ to be built in the UK? If we are able to retrofit full free-flow to an existing junction, whoever's in government, I will buy a hat and digest it.
- crowntown100
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Re: A3/M25 Wisley Upgrade
No, because A1 N/Bound > M62 E/bound in through the old stackabout, as is M62 W/bound to A1 S/Bound. Strategically it is covered by the M18 from the A1(M) to the M62.Johnathan404 wrote:Am I right in thinking M62/A1(M) was the most recent four-way full GSJ to be built in the UK?
Re: A3/M25 Wisley Upgrade
The M62/A1(M) junction isn't a full free-flow, though – traffic between the south and east has to use the old Ferrybridge roundabout. (That isn't a criticism of the junction, I think it's perfectly appropriate to the needs of the fairly small amount of traffic making that turn, but it isn't a full free-flow).Johnathan404 wrote:Am I right in thinking M62/A1(M) was the most recent four-way full GSJ to be built in the UK? If we are able to retrofit full free-flow to an existing junction, whoever's in government, I will buy a hat and digest it.
Re: A3/M25 Wisley Upgrade
The M62/A1(M) junction isn't a full free-flow, though – traffic between the south and east has to use the old Ferrybridge roundabout. (That isn't a criticism of the junction, I think it's perfectly appropriate to the needs of the fairly small amount of traffic making that turn, but it isn't a full free-flow)./quote]Yes, that's right. I wonder if there was any reason other than cost for not making it free-flow.Stevie D wrote:Johnathan404 wrote:Am I right in thinking M62/A1(M) was the most recent four-way full GSJ to be built in the UK? If we are able to retrofit full free-flow to an existing junction, whoever's in government, I will buy a hat and digest it.
Am I not right in thinking it wasn't considered that way until the upgrade was completed?? I don't recall the M18 being considered that way before then.crowntown100 wrote:No, because A1 N/Bound > M62 E/bound in through the old stackabout, as is M62 W/bound to A1 S/Bound. Strategically it is covered by the M18 from the A1(M) to the M62.
Re: A3/M25 Wisley Upgrade
Not sure I understand this. Nothing changed when the present Ferrybridge Interchange opened in 2005. Traffic between the south and Hull went via the M18 before then and still goes that way now. The turning movement at Ferrybridge between the south and the east is only really for local traffic.Berk wrote:Am I not right in thinking it wasn't considered that way until the upgrade was completed?? I don't recall the M18 being considered that way before then.crowntown100 wrote:No, because A1 N/Bound > M62 E/bound in through the old stackabout, as is M62 W/bound to A1 S/Bound. Strategically it is covered by the M18 from the A1(M) to the M62.
Roads.org.uk
Re: A3/M25 Wisley Upgrade
The reason for not making it free-flow is largely geography: http://www.streetmap.co.uk/map.srf?X=44 ... 2287&Z=120Berk wrote:Yes, that's right. I wonder if there was any reason other than cost for not making it free-flow.
Am I not right in thinking it wasn't considered that way until the upgrade was completed?? I don't recall the M18 being considered that way before then.
The new junction is well to the north-west of the old Ferrybridge interchange, so incorporating what would effectively be a U-turn within that would add a whole lot of complication (and cost, yes) that would be unnecessary and irrelevant – the extra distance involved in going up to the interchange and back on a parallel road means that it would probably take longer than using the old roundabout, and the relatively small volume of local traffic that makes that turn really doesn't justify anything better than what's already there. It's really only traffic between Selby and the south, and between Hull and the northernmost tip of Doncaster or Elmsall. For pretty much everything else, the M18 is a better bet, and has been for the 35 years that the motorway has been open.
Re: A3/M25 Wisley Upgrade
A friend of mine has designed a fantasy layout or two for that, not meant to be taken too seriously. I now have a scanner, so next time I see them I'll scan them in.mapalex wrote:Hi,
The government plans to make the A3/M25 Wisley interchange one with free flowing links, as part of its new 'investment plan', over the next five years.
I was wondering how engineers would actually go about it. Would they use the existing roundabout in a new way and adapt it? Or would they create completely new structures and then remove the roundabout?
Either way it sounds like a big undertaking.
Alex
The same question arises for the M1/M62 at Lofthouse, with the additional complication of the B road.
Re: A3/M25 Wisley Upgrade
As far as the freeflow links at Wisley are concerned I would say they'll just be left turn filter lanes. All directions can easily be interpreted as all four left turns. To completely rebuild the junction as a full freeflow will be hugely expensive and the existing footprint of the junction is too small to allow decent radii on the slips.
Those on the Dublin M50 shows it's possible to rebuild roundabout GSJ's but I don't see it happening at Wisley.
Big and complex.
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Re: A3/M25 Wisley Upgrade
Four left filter lanes would be easy enough to do. I'd go for a M25/M1 style junction, with slips from A3N to M25E and M25E to A3S. There would be enough residual capacity on the roundabout to deal with the remaining two movements.
As for the LILO local roads, they could be joined with an overbridge, as access is provided at the very adjacent Ockham junction. There is plenty of land available here to get the work done.
I have a contact at Surrey CC who has mentioned both this and the A3 though Guildford (not really a bypass is it?!) recently so I'll see if I can find out anything.
Re: A3/M25 Wisley Upgrade
I'd agree, as the M25 directions into London aren't strategically important, and there are local accesses into the mix. However, I'd have thought that bridges or underpasses to make free flowing links out of London seem a good idea...guvvaA303 wrote:As a regular and local user of this junction, I'd say that not all movements are required to be FF.
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Re: A3/M25 Wisley Upgrade
In a fantasy world it would be full free flow with the A3 as a motorway from Esher to the M27 (let's call it the M28).
Terminally cynical, unimpressed, and nearly Middle Age already.
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Re: A3/M25 Wisley Upgrade
Being a "local" I know where to avoid, and high on my list is the M3 to M25 in the rush hours, and the M25 from Reigate to M4 in the mornings and from M4 to M3 in the evenings (unless one is going M3 north).
How people commuting those routes/times put up with the normal huge queues almost every day I cannot understand. I always wonder how the DoT models don't prioritise mods to the roads based on wasted time/fuel.
Re: A3/M25 Wisley Upgrade
Which are the heavy right-turn flows at the junction? A3 northbound to M25 eastbound? It would be good if they could get a direct slip as well, like at the A2/M25 junction.