A3/M25 Wisley Upgrade

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Herned
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Re: A3/M25 Wisley Upgrade

Post by Herned »

A303Chris wrote: Thu May 13, 2021 09:26 The decision from the SoS put back another 6 months for Environmental Issues to be resolved, until November 2021.

I bet nothing happens now, schemes like this to quietly drop of as the cost of the pandemic hits the governments finances.
Good! Replacing a roundabout with a bigger roundabout has always seemed madness to me. Do it properly or don't bother
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Chris5156
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Re: A3/M25 Wisley Upgrade

Post by Chris5156 »

A303Chris wrote: Thu May 13, 2021 09:26 The decision from the SoS put back another 6 months for Environmental Issues to be resolved, until November 2021.

I bet nothing happens now, schemes like this to quietly drop of as the cost of the pandemic hits the governments finances.
This is one RIS2 scheme I wouldn’t be at all unhappy to see the back of. It’s an absolute waste of £250m.
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Bryn666
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Re: A3/M25 Wisley Upgrade

Post by Bryn666 »

Chris5156 wrote: Thu May 13, 2021 09:59
A303Chris wrote: Thu May 13, 2021 09:26 The decision from the SoS put back another 6 months for Environmental Issues to be resolved, until November 2021.

I bet nothing happens now, schemes like this to quietly drop of as the cost of the pandemic hits the governments finances.
This is one RIS2 scheme I wouldn’t be at all unhappy to see the back of. It’s an absolute waste of £250m.
Agreed, divert that £250m into sorting out urban junctions so they're safe for cycling and walking instead. Much bigger return on spend and social value is proven.
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A320Driver
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Re: A3/M25 Wisley Upgrade

Post by A320Driver »

Add me to the list of those hoping this gets sent back to the drawing board and done properly.
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jackal
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Re: A3/M25 Wisley Upgrade

Post by jackal »

marconaf wrote: Fri Jan 22, 2021 18:31
jackal wrote: Fri Jan 22, 2021 17:24
Really interesting data.

The right hand turns are:

A3 south to M25 west - 1550
M25 west to A3 south - 1010
M25 east to A3 north - 498
A3 north to M25 east - 378

So the biggies are the two I suggested, of which the A3 south is 50% larger as I thought. So the option with freeflow for that alone seems a clear winner as that would leave the roundabout free to accomodate the others. Throw in left turns to cut those bits out of the roundabout and job done!

As proposal 7 basically. Seems odd that didnt go through - the others do have huge land take.
Here's a late, and I'm afraid tedious, reply.

There are two ways of reading the table, depending on what is meant by North, South, East, West. On the literal construal North means North (i.e., the arm of the junction the traffic is coming from or going to). On the figurative construal North means Northbound (i.e., the direction of travel).

On the literal interpretation we have these right turns:

M25 West to A3 South 1010
M25 East to A3 North 495
A3 North to M25 West 1311
A3 South to M25 East 1237

On the figurative interpretation we have these right turns:

M25 Westbound to A3 Northbound 1138
M25 Eastbound to A3 Southbound 1112
A3 Northbound to M25 Eastbound 378
A3 Southbound to M25 Westbound 1553

Your numbers are a mixture of the two interpretations (plus a few typos for final digits).

The correct interpretation is the literal interpretation. This can easily be seen from the fact that M25 East to A3 North is by far the least busy right turn, as a perusal of a map would suggest, whereas it is a busy movement (called "M25 Westbound to A3 Northbound") on the figurative interpretation.

This is confirmed by the fact that there's a good match between the two halves of movement pairs on the literal construal but not the figurative construal. E.g., North to West and West to North have 1311 and 1138 respectively, whereas on the figurative interpretation the same movements, called Southbound to Westbound and Eastbound to Northbound, have 1553 and 495 respectively, which is a nonsense.

So as I said in the previous post, "Volumes are similar for 6/8 turning movements. A3 North to/from M25 East is much lower".

If I were SABRE king my first act would be to ban all use of figurative "bound" directions when talking about junctions, which causes endless confusion.
Last edited by jackal on Fri May 14, 2021 14:52, edited 2 times in total.
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wrinkly
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Re: A3/M25 Wisley Upgrade

Post by wrinkly »

jackal wrote: Fri May 14, 2021 14:45 If I were SABRE king my first act would be to ban all use of figurative "bound" directions when talking about junctions, which causes endless confusion.
I strongly support this. I remember posting about it years ago.
My second act would be to impose more consistent terminology about temporary termini versus temporary tie-ins.
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Re: A3/M25 Wisley Upgrade

Post by A320Driver »

New SoS determination date set as 12th May 2022, 16 month delay.
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Re: A3/M25 Wisley Upgrade

Post by Micro The Maniac »

The Secretary of State received the examining authority’s report on 12 October 2020 and the current deadline for a decision was 12 November, having been extended from 12 January 2021 to 12 May 2021 and then to 12 November 2021. The deadline is now extended to 12 May 2022.
https://www.gov.uk/government/speeches/ ... ing-update

The SoS should get his big red "Rejected" stamp out, and be done with it
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Re: A3/M25 Wisley Upgrade

Post by A320Driver »

DCO granted, with construction set to start later this year.

It’s still a monumental waste of a quarter of a billion pounds.
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Re: A3/M25 Wisley Upgrade

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A320Driver wrote: Fri May 13, 2022 00:08DCO granted, with construction set to start later this year.

It’s still a monumental waste of a quarter of a billion pounds.
Agreed - I've probably ground this axe enough, but it's the most remarkably irresponsible misuse of public funds. I'm generally happy to see the current ambition for the strategic road network, and money being spent to match it, but this is such an abominable waste.
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A303Chris
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Re: A3/M25 Wisley Upgrade

Post by A303Chris »

If anyone wants to see the consented plans they are here

Basically, the improved scheme includes the following.

• Dedicated left turn slip roads from all off slips onto the adjacent on slip
• Widening the A3 to four lanes in both directions between the Ockham Park junction to the M25 and then from the M25 to the Cobham junction
• Closing the Wisley Lane slips from the A3 northbound and providing a new bridge over the A3 and diverting Wisley Lane to the south of the A3 and connecting it to the Ockham Park roundabout
• Signalising the Ockham Road roundabout
. Dedicated free flow lanes on north side of Painshill junction
• Providing 4 lanes on the M25 through the junction.

One huge sticking plaster, needed to be like the Darenth junction with a flyover from the M25 anti clockwise to A3 southbound and a dedicated slip from A3 north to M25 clockwise
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Re: A3/M25 Wisley Upgrade

Post by Bryn666 »

M6 J10 syndrome, where the only output is "moar lanez" and "biggur rundboutz" as if a toddler was asked to develop the scheme.

If a signalised roundabout currently does not work, why would anyone think making a slightly bigger signalised roundabout will make a difference? This is exactly why people point at new roads and go "they just fill up with traffic".
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ChrisH
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Re: A3/M25 Wisley Upgrade

Post by ChrisH »

Looking at the details of the roundabout I am still baffled on two counts:

Firstly the "free flow" left turns diverge so close to the stopline that even a moderate amount of queuing is going to obstruct the free flow. This has been pared to the bone on a £250m scheme :confused:

Secondly the new bridges are absolutely enormous with verges either side, and four traffic lanes. But logically the traffic signals mean that only two of the lanes will typically be occupied at any time, because flows are relatively balanced so the signals will sequence right turning traffic through several stoplines at a time. In this case I struggle to see the marginal benefit over and above keeping the existing bridges and adding the left-turn free-flow lanes.
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Re: A3/M25 Wisley Upgrade

Post by Truvelo »

If freeflow left turns are going to be the only real benefit then why not add them to the existing roundabout and save £200m in the process. On another note, I was trying to look on streetview to see if they would fit in the existing junction and it appears the Google car driver was highly intoxicated :)

https://goo.gl/maps/tybZEyE3DN4va5Ph6
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Chris5156
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Re: A3/M25 Wisley Upgrade

Post by Chris5156 »

ChrisH wrote: Fri May 13, 2022 10:10Firstly the "free flow" left turns diverge so close to the stopline that even a moderate amount of queuing is going to obstruct the free flow. This has been pared to the bone on a £250m scheme :confused:
Ugh. The southbound exit has the two-lane sliproad developing into three lanes, all of which are for right turns, and the free-flow left turn then branches off that. For zero extra pounds you could have that third lane dedicated to left turns, which would extend the length of queue immunity for left turning traffic. But presumably that reduced the available stacking space for right turners so the modelling said no.
Secondly the new bridges are absolutely enormous with verges either side, and four traffic lanes. But logically the traffic signals mean that only two of the lanes will typically be occupied at any time, because flows are relatively balanced so the signals will sequence right turning traffic through several stoplines at a time. In this case I struggle to see the marginal benefit over and above keeping the existing bridges and adding the left-turn free-flow lanes.
This is very true and an interesting thought. I'd add to that the observation that, at present, even in rush hour, the roundabout itself doesn't lock up. Once you're on it you move around and the signals are well timed to get you through the junction without queues blocking movements further back. The issue is getting on to the roundabout. This really is quarter of a billion pounds for some very marginal gains.

That said - the widening to four lanes on each A3 approach, and the diversion of the local road to Wisley to reach the Ockley junction roundabout, is very welcome and money well spent. It's the roundabout like-for-like replacement that I just can't get behind.
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Re: A3/M25 Wisley Upgrade

Post by Fluid Dynamics »

I completely agree that the proposals for Junction 10 are a complete waste of money.

The rest of the schemes has some benefits, namely getting rid of the awful access to Wisley from the A3 and the conflicts that causes on the A3 northbound. However, some of benefits are lost by keeping the Ockham junction arrangement as it is with no south facing slips. That means all traffic accessing Wisley to or from the A3 south is either going to have to travel through Ripley, or use the new junction 10 roundabout, placing more strain on that inadequate 'improvement'.
Last edited by Fluid Dynamics on Fri May 13, 2022 17:19, edited 1 time in total.
jnty
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Re: A3/M25 Wisley Upgrade

Post by jnty »

Fluid Dynamics wrote: Fri May 13, 2022 16:57 I completely agree that the proposals for Junction 10 are a complete waste of money.

The rest of the schemes has some benefits, namely getting rid of the awful access to Wisley from the A3 and the conflicts that causes on the A3 northbound. However, some of benefits are lost by keeping the Ockham junction arrangement as it is with no south facing slips. That means all traffic accessing Wisley to or from the A3 south is either going to have to travel through Ripley, or use the new junction 10 roundabout, placing more rain on that inadequate 'improvement'.
I hadn't spotted that - what a bizarre decision!
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Re: A3/M25 Wisley Upgrade

Post by SouthWest Philip »

In addition to pointless and expensive enlargement of the roundabout, I cannot see how widening the M25 to four lanes each way through the junction helps. So much traffic joins and leaves here that eliminating the lane drops/lane gains will surely make things worse?

(Jnc 11, on the other hand...)
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jackal
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Re: A3/M25 Wisley Upgrade

Post by jackal »

I think the four lane M25 will be or has been dropped due to the ALR hiatus. The general arrangement is dated 2019.
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Re: A3/M25 Wisley Upgrade

Post by Chris5156 »

SouthWest Philip wrote: Fri May 13, 2022 17:07In addition to pointless and expensive enlargement of the roundabout, I cannot see how widening the M25 to four lanes each way through the junction helps. So much traffic joins and leaves here that eliminating the lane drops/lane gains will surely make things worse?
Jackal's observation notwithstanding, it is certainly an interesting design choice from an organisation that is feverishly inserting new and barely-justified lane drops on other motorways nearby.
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