M3 Junction 9 Improvements

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Bryn666
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Re: M3 Junction 9 Improvements

Post by Bryn666 »

Yes, the real issue here is the weaving. Not the offside diverge.
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Re: M3 Junction 9 Improvements

Post by Richardf »

I think it's very shortsighted developing what looks like a great scheme and leaving the A34/A33 junction as it is and worse adding to its weaving issues.

I know it wouldn't really solve the weaving entirely but adding an extra lane to this section and making the section where changing lanes will take place a bit longer, would make it a bit safer and must be possible to do?
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Re: M3 Junction 9 Improvements

Post by jackal »

6637 wrote:That section of weaving could be ameliorated (though not completely removed) by simply swapping the locations of the proposed Highways England access road and the J9 northbound onslips.

This wouldn't remove the weaving, of course, but it would increase the length of road in which the weaving occurs.
Or leave the M3 onslip as per the proposal, but use an extension of the existing M3 onslip for access to the A34/A33:
M3 A34 alternative - Copy.png
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Re: M3 Junction 9 Improvements

Post by wrinkly »

Bryn666 wrote:An offside exit is hardly impossible to deal with is it...

We don't have carnage in Newcastle or Leeds where offside exits are in use daily.
But those are in city centres, not on a rural trunk road.
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Re: M3 Junction 9 Improvements

Post by Bryn666 »

The principle is the same, with adequate signing an offside exit should not be a shock to a driver.

I'm not saying they should be everywhere but their presence is not a problem.
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Re: M3 Junction 9 Improvements

Post by Johnathan404 »

More evidence that the finer details have been overlooked:
"This [M3 northbound exit] slip road is currently proposed to be two lanes, potentially widening to three lanes on the approach to the new roundabout arrangement."

There's only one exit! Anyone wanting the A33, A34 or M3 would have gone under the roundabout, anyone wanting the A272, A31 or Winchester would have used M3 J10, leaving us with only Winnall Trading Estate and the Highways England depot. Three lanes for these seems a bit excessive, considering Easton Lane itself is only planned to have two lanes.
darkcape wrote:Correct me if I'm wrong but didn't the A34/A33 originally open as 2 through lanes with a right-hand exit before being remarked in the mid 2000's - I'm assuming because they didn't like RH exits - so I wonder why it is being reinstated.
I don't remember that. It wasn't a problem until the M3 opened in 1985, and even after that it would have taken time for the A34 to truly fill up. Street View does show us that the Highways Agency, in their wisdom, removed some road markings in the mid-2000s, but without changing the layout.
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Re: M3 Junction 9 Improvements

Post by Glom »

New video from HE on the YT. So there is dumbell with free flow slips. And I think I spied four lanes with hard shoulder under the bridge. Very nice.
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Re: M3 Junction 9 Improvements

Post by jackal »

The consultation report is out and the preferred route announcement will be made on the 24th: https://highwaysengland.co.uk/projects/ ... rovements/

As I didn't post it previously, here's the rejected option 11, which removes the northbound weaving and offside exit at the cost of an extra £50m and three additional bridges:

M3 J9 option 11 - Copy.PNG
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Re: M3 Junction 9 Improvements

Post by jackal »

The preferred route has been announced. It appears to be simply the consulted option (option 14).

They say they're looking in more detail at the 'A33/A34 merging section', though really the problems of weaving with an offside diverge are fundamental to the design. It's a bit of a missed opportunity to fix things once and for all, option 11-style (see above). But it should still be a very good improvement overall.

https://highwaysengland.citizenspace.co ... chure1.pdf
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Re: M3 Junction 9 Improvements

Post by Johnathan404 »

So their conclusion was it's a great design apart from the big design flaw with it?
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Re: M3 Junction 9 Improvements

Post by Berk »

Hopefully there’s enough time for them to backtrack if they want to...
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Re: M3 Junction 9 Improvements

Post by jackal »

One of the reasons given for rejecting option 11 was that it would mean A33 traffic still had to go through the roundabout. But they could actually add an extra little slip from the new A34NB mainline to the A33. As it would be on the offside at the existing A33/A34 exit it could be arranged so it didn't pose weaving issues.
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Re: M3 Junction 9 Improvements

Post by Truvelo »

Is there really enough traffic travelling from the M3 south to the A33 to really clog up the roundabout once all A34 traffic has been eliminated?
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Re: M3 Junction 9 Improvements

Post by Johnathan404 »

I'm now convinced the best option would be a new nearside northbound offslip leading to the B3047 London Road. I appreciate it would be expensive, but not only does it solve the weaving problem (I'd suggest three lanes between the slips), there are two additional benefits which I haven't heard mentioned yet:

1) The A33/B3047 crossroads at the end of the Bypass is an accident blackspot, because people pulling out don't appreciate how fast traffic is coming off the A34. By closing the old northbound offslip you would be halving the number of conflicts at this junction, as traffic leaving Winchester would be able to join the A33 at these crossroads without having to give way to anything, and traffic turning right to enter Winchester would again not have any oncoming traffic to give way to.

Granted it would slightly undo the effect of the Winchester Bypass by routing northbound traffic past the Kings Worthy Post Office which hasn't happened since the 1930s, but it's hardly densely developed and has problems with people queueing to join the A33 anyway.

2) Closing the old northbound offslip onto the A33 would free up land that could be sold to the neighbouring business park, making back some of the money spent (not my idea of a great outcome but they'll be filling the place with development anyway).
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Re: M3 Junction 9 Improvements

Post by jackal »

Truvelo wrote: Thu Jul 26, 2018 16:54 Is there really enough traffic travelling from the M3 south to the A33 to really clog up the roundabout once all A34 traffic has been eliminated?
Enough to make option 14 (with the weaving) apparently have higher benefits as well as lower costs. Though I feel that their BCR can't fully account for the impact on flow and safety from having such a tight mainline weaving space combined with an offside exit.
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Re: M3 Junction 9 Improvements

Post by jackal »

Further to the above, I looked at the accident projections in the TAR:

OPTION 11 OPTION 14
Number of ‘Without’ Scheme Accidents 20,376 20,376
Number of ‘With’ Scheme Accidents 19,730.7 19,752.5
Total Number of Accidents Saved by Scheme 645.3 623.5
Total Accident Benefits Saved by Scheme (£M) £30.407 £28.580

So even in safety terms, the benefit of removing a 200 metre weaving space including offside exit from the A34 mainline is pretty trivial (over the assessment period 22 accidents, presumably minor given their £2m total monetized cost). If that were true we could tear up TD 22/06 and just throw in merges and diverges wherever we feel like it.

More likely this is an impactful limitation:
This analysis could only identify Personal Injury Accidents that would have been saved during the period assessed. It could not identify what new safety concerns, potentially other accidents, that could be generated as a result of the scheme option.
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Re: M3 Junction 9 Improvements

Post by Richardf »

So assuming this goes ahead, how will they go about building it? What do you think will be done first?

Went through the Junction recently and it got me thinking. Given how busy it is, traffic management while they build the new junction is going to be 'interesting' to say the least!
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Re: M3 Junction 9 Improvements

Post by RichardA35 »

Richardf wrote: Fri Nov 09, 2018 20:55 So assuming this goes ahead, how will they go about building it? What do you think will be done first?

Went through the Junction recently and it got me thinking. Given how busy it is, traffic management while they build the new junction is going to be 'interesting' to say the least!
Broad approach will be to build what can be done offline first then transfer traffic onto these links to generate space to build the trickier bits and so on.
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Re: M3 Junction 9 Improvements

Post by mikehindsonevans »

RichardA35 wrote: Sat Nov 10, 2018 11:08
Richardf wrote: Fri Nov 09, 2018 20:55 So assuming this goes ahead, how will they go about building it? What do you think will be done first?

Went through the Junction recently and it got me thinking. Given how busy it is, traffic management while they build the new junction is going to be 'interesting' to say the least!
Broad approach will be to build what can be done offline first then transfer traffic onto these links to generate space to build the trickier bits and so on.
Two things:
1. "RichardA35" post - yes the TM will be interesting; we're moving to Cheshire!
2. Weaving just north of the J9 roundabout, up the A34 NB. There is a sub-population of drivers who carve up the outside lane on the A34 north of M3j9. They do this because, on approaching M3j9 from the South, there are huge HE/HA signs saying - quite clearly - "For A34 use both lanes". They then have about 0.8 of a mile to drive in both lanes before the "Holy F***, thank heavens for ABS" moment when it becomes clear that the Offside lane is exclusively for the A33 and Kings worthy. Cue braking, squeezing, wailing and gnashing of bumpers! Obviously HA team 1 (south of the junction, M3j9NB approach) never consulted with HA team 2 (A34/A33 north of the junction) - or the person responsible was subsequently savaged to death by his/her guide dog???

As a quick and dirty interim suggestion, could I suggest that HA/HE go out one night (soon!) with a bit of white paint and mark BOTH lanes, north of the M3j9 junction with "A34 NORTH" allocations, plus "A33" in the offside of the two lanes as well? The massively overwhelming major flow of traffic is to the A34 (most/many people for Kings Worthy and the old A33 go round the back, to avoid the madness of j9). But add a couple of speed cameras - this is one place where they would be justified.

In terms of weaving and speed and impacts, the 50mph limit lasts until beyond the A33nb diverge, so let's at least try this?

Please??
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Re: M3 Junction 9 Improvements

Post by Johnathan404 »

mikehindsonevans wrote: Sat Nov 10, 2018 13:06 2. Weaving just north of the J9 roundabout, up the A34 NB. There is a sub-population of drivers who carve up the outside lane on the A34 north of M3j9. They do this because, on approaching M3j9 from the South, there are huge HE/HA signs saying - quite clearly - "For A34 use both lanes". They then have about 0.8 of a mile to drive in both lanes before the "Holy F***, thank heavens for ABS" moment when it becomes clear that the Offside lane is exclusively for the A33 and Kings worthy. Cue braking, squeezing, wailing and gnashing of bumpers! Obviously HA team 1 (south of the junction, M3j9NB approach) never consulted with HA team 2 (A34/A33 north of the junction) - or the person responsible was subsequently savaged to death by his/her guide dog???
It is not an accident, they are two different junctions. There are plenty of junctions where advice is given at one which changes at the next. In fact, you could argue that it’s better than what happens at M40 J9, where it says “use all lanes for Oxford A34” and then on the other side of the roundabout the third lane ends!

The signs are there to reduce the length of the queue leaving the M3 by doubling the number of vehicles which get through the traffic lights. It’s slightly academic these days as most of the time the queue to leave brings the M3 to a crawl anyway.

I doubt any of the people who cut in at any moment are surprised by the layout. They are deliberately leaving it as late as they dare. Though I wouldn’t do it on principle, the quickest way to join the A34 is to leave it until the very last moment and cut in right before the split, as at this point the A34 is already wide enough to form two lanes and is usually free-flowing.

I agree that seeing as the re-marked right-hand exit is part of the approved scheme, they should do this part ASAP and leave the difficult parts until they’re ready.

I’m not sure the TM will be that difficult. The re-aligned A34 can be built first, the flyover will cross the quieter part of the M3, and as soon as it’s open the amount of traffic will drop dramatically.
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