A3/M25 Wisley Upgrade

[M4 Cardiff]

Drove through this junction today and noticed that there has been significant vegetation clearance and the yellow vultures are up on both the A3 and the M25, but not switched on yet.

[Chris5156]

Speed and lane restrictions started today. Southbound this morning around 9am, the road was open at full speed; northbound this evening at about 7pm the 50 limit was in force and the right-hand lane is now signposted for a 6'6" width restriction and has been narrowed with cones.

The northbound exit slip from the A3 to the roundabout has been coned down from four lanes to two - that's going to make Monday morning rush hour interesting if it remains in place.

Big new signs on the verge - which I don't recall seeing before - announce the scheme, and a completion date of Summer 2025. Two and a half years to go before the old signalised roundabout is gone and we have our brand new signalised roundabout!

[Vierwielen]

Speed and lane restrictions started today. Southbound this morning around 9am, the road was open at full speed; northbound this evening at about 7pm the 50 limit was in force and the right-hand lane is now signposted for a 6'6" width restriction and has been narrowed with cones.

The northbound exit slip from the A3 to the roundabout has been coned down from four lanes to two - that's going to make Monday morning rush hour interesting if it remains in place.

Big new signs on the verge - which I don't recall seeing before - announce the scheme, and a completion date of Summer 2025. Two and a half years to go before the old signalised roundabout is gone and we have our brand new signalised roundabout!

Sounds like a carbon copy of what was happening there 25 years ago when I was commuting to Kingston - going up the A3, but coming home via the M3.

[Chris5156]

I tell a lie - speed restrictions are still only northbound. Southbound remains at 70, for the time being, though I doubt it will stay that way for long.

[davidsouthwell]

What an extremely depressing read this all was. I love roundabouts, but on major motorways they just shouldn't even be considered. Can we all collectively come together and blame the people of Bracknell for protesting against and ultimately preventing the building of the M31 around South-West of the town in the 70s? What a difference it would make alongside providing full grade seperated junctions at the A404 Handy Cross and A404(M) Hollyport junctions. We'd have a full bypass of the M25 between the M40 and the M3, with potential to continue further to the A3 if needed. I'm still young, I can still dream of seeing the beautiful partially-unrolled cloverleaf at the M4 J10 (A329(M)) junction finally being used to its full potential. Its such a waste in its current form, rubbing salt into the wound with the downgrade to 1 lane on the A329(M) through the junction in 2014. Its basically turned the A329(M) into a single lane road with a feeder for the M4. The lane hogging and weaving is insane, the congestion is really starting to get bad now.

[BOH]

What an extremely depressing read this all was. I love roundabouts, but on major motorways they just shouldn't even be considered. Can we all collectively come together and blame the people of Bracknell for protesting against and ultimately preventing the building of the M31 around South-West of the town in the 70s? What a difference it would make alongside providing full grade seperated junctions at the A404 Handy Cross and A404(M) Hollyport junctions. We'd have a full bypass of the M25 between the M40 and the M3, with potential to continue further to the A3 if needed. I'm still young, I can still dream of seeing the beautiful partially-unrolled cloverleaf at the M4 J10 (A329(M)) junction finally being used to its full potential. Its such a waste in its current form, rubbing salt into the wound with the downgrade to 1 lane on the A329(M) through the junction in 2014. Its basically turned the A329(M) into a single lane road with a feeder for the M4. The lane hogging and weaving is insane, the congestion is really starting to get bad now.

Was it the folks from Bracknell who largely protested or more in leafy Surrey? I agree, that road now would make such a huge difference to traffic levels.

[Patrick Harper]

This scheme effectively represents how Wisley should have been built originally, except that the junction as built is not dramatically worse, in-fact it was quite space-efficient. With four running lanes through J10 and J11, and five running lanes between J11 and J12 it would seem that the J10 to J11 section will become the new bottleneck by the end of the decade.

The 1980s bridges must have taken a lot of weight over the years, is there a case to be made for instating new bridges in that disruption would be reduced in case the old ones were found to have become defective?

[AnOrdinarySABREUser]

Big new signs on the verge - which I don't recall seeing before - announce the scheme, and a completion date of Summer 2025. Two and a half years to go before the old signalised roundabout is gone and we have our brand new signalised roundabout!

Better be waiting for the 2040 rendition of these improvements, this time with an even bigger roundabout. I'm sure congestion will be solved around that time!

[Mapper89062]

It's highly annoying that they're building two new bridges over the M25 yet not leaving any space for extra lanes. If there was room for that, then restoring the plan for D4M under the junction would be as simple as demolishing the old bridges, taking a bit of land around the motorway for new hard shoulders, then remarking the current shoulder as a running lane, which would have minimal cost compared to building new bridges and the other improvements proposed here.

[SouthWest Philip]

It's highly annoying that they're building two new bridges over the M25 yet not leaving any space for extra lanes. If there was room for that, then restoring the plan for D4M under the junction would be as simple as demolishing the old bridges, taking a bit of land around the motorway for new hard shoulders, then remarking the current shoulder as a running lane, which would have minimal cost compared to building new bridges and the other improvements proposed here.

Unless you're going to widen the M25 to D5 or D6 either side, which I wouldn't advocate, there is no point increasing capacity through the junction as there is more than enough traffic leaving and entering to justify the lane drop. Unlike jnc 11!

I think, broadly speaking, anything above D4M represents a failure of imagination in dealing with the problem. Far better to either build parallel routes to spread the load or reduce the load by improving public transport on the the highest demand routes.

[jackal]

With four running lanes through J10 and J11, and five running lanes between J11 and J12 it would seem that the J10 to J11 section will become the new bottleneck by the end of the decade.

The ALR scheme for four running lanes through J10 and J11 has been dropped subsequent to your post, though it was on hold at the time and looked highly improbable.

There was no scheme for five lanes between J11 and J12 (I've long advocated it here). The only between-junction ALR that was proposed as part of the J10-J16 scheme was J15 to J16.

https://nationalhighways.co.uk/our-road ... terchange).

It's highly annoying that they're building two new bridges over the M25 yet not leaving any space for extra lanes. If there was room for that, then restoring the plan for D4M under the junction would be as simple as demolishing the old bridges, taking a bit of land around the motorway for new hard shoulders, then remarking the current shoulder as a running lane, which would have minimal cost compared to building new bridges and the other improvements proposed here.

The existing bridges are sufficient for four lanes with no HS (intermittent HS is not banned, as seen on the Simister scheme). According to the drawing (sheet 5) the new bridges are significantly wider than the existing bridges: https://infrastructure.planninginspecto ... %2031).pdf

Of all the complaints one could have with this scheme, not allowing the M25 to be widened to 5 or 6 lanes through this busy junction, where it needs no more than three, is pretty far down there.

[Richardf]

Just seen a youtube video of this project. What a joke! How long will the benefits of this scheme (if any) last. Looks a total waste of money to me.

[Fluid Dynamics]

Just seen a youtube video of this project. What a joke! How long will the benefits of this scheme (if any) last. Looks a total waste of money to me.

Whilst I agree that the A3/M25 interchange 'improvements' are sub-optimal and worse than many of the other options, the scheme does introduce free flow left hand turns at the new roundabout.

However, the greater benefit is on the A3 which will get better treatment of access to RHS Wisley which was previously dangerous, with slow traffic merging with the A3 shortly before the M25 junction, and widening of the A3 approaches. However even here the job is only half done, as traffic from/to the south on the A3 will need to make lengthy diversions to access Wisley due to the lack of south facing slips at the Ockham Junction that easily cold have been added by the project.

[jervi]

Plus there are significant improvements for NMUs along the A3 & over the M25.

[Fluid Dynamics]

Plus there are significant improvements for NMUs along the A3 & over the M25.

Agreed.

[Big L]

Plus there are significant improvements for NMUs along the A3 & over the M25.

I passed through last weekend and half of the new footbridge just to the south of the junction has been lifted (presumably) into place. Northbound traffic passes beneath.

[ChrisH]

According to the project webpage there are some closures coming up for this scheme:

Throughout 2024 there will be other full weekend closures of the A3 and M25.

The first two closures are:

Friday 23 February 9pm to Monday 26 February 6am the A3 will be closed in both directions between Send and M25 Junction 10 Wisley Interchange, for demolition works.

Friday 15 March 9pm to Monday 18 March 6am the M25 between junction 10 and 11 in both directions, for demolition works and gantry installation.

Yes, a full closure of the M25. All weekend. I had always understood that the only permissible hours for M25 closures were 10pm-5am. How has this been arrived at, and what will Surrey look like with the M25 closed for a whole weekend?

[Bryn666]

According to the project webpage there are some closures coming up for this scheme:

Throughout 2024 there will be other full weekend closures of the A3 and M25.

The first two closures are:

Friday 23 February 9pm to Monday 26 February 6am the A3 will be closed in both directions between Send and M25 Junction 10 Wisley Interchange, for demolition works.

Friday 15 March 9pm to Monday 18 March 6am the M25 between junction 10 and 11 in both directions, for demolition works and gantry installation.

Yes, a full closure of the M25. All weekend. I had always understood that the only permissible hours for M25 closures were 10pm-5am. How has this been arrived at, and what will Surrey look like with the M25 closed for a whole weekend?

If properly advertised in advance, it'll be like the infamous Carmaggeddon when I-405 was shut for a weekend in Los Angeles; everything promised sheer meltdown, so nobody travelled. Job done.

[Chris5156]

Yes, a full closure of the M25. All weekend. I had always understood that the only permissible hours for M25 closures were 10pm-5am. How has this been arrived at, and what will Surrey look like with the M25 closed for a whole weekend?

I fear this is “normal” now - extended closures of critical roads for the convenience of construction project planning. The M4 Smart Motorway works got away with murder in this respect and there wasn’t nearly enough push back to prevent it happening again.

I don’t really know what they’re demolishing that will take a whole weekend, though - all the existing interchange bridges are remaining when the scheme is complete, so it’s not those. There’s an accommodation bridge over the M25 just west of the interchange that might need replacing to make room for the extended sliproads - is that it?

[AnOrdinarySABREUser]

Plus there are significant improvements for NMUs along the A3 & over the M25.

Yes, but there are better ways of improving such an important junction like J10 of the M25. Just because this option includes improvements to NMU infrastructure doesn't mean that the other options didn't.