M3 Junction 9 Improvements

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Richardf
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Re: M3 Junction 9 Improvements

Post by Richardf »

Johnathan404 wrote: Wed Jul 03, 2019 10:24
SteveA30 wrote: Tue Jul 02, 2019 21:33 I'm sure the A33 was simply a diverge off the outside lane of the A34 in pre-M3 days, not the separate lanes of now. It didn't cause any problems. Overtakers on both roads just had to wait until after the diverge, when the 2 lines of lorries took their respective roads.
I don't want to doubt you, but that is a surprise. The traffic flow would have been evenly split in the pre-M3 days, possibly even heavier on the A33 side. Until 1967 the A34 didn't even get a look in, with traffic having to go through Winchester before meeting the A33.
I know this has probably been discussed plenty of times before but in the past (ie post A34 bypass but pre M3) wouldnt the A33 have been the mainline here and the A34 a sliproad?
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Re: M3 Junction 9 Improvements

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The A33 certainly seemed busier. The separate lanes came in a few years after the M3 extension opened (May 85), perhaps 1990. I recall being surprised by the new layout and wondering why is was introduced when the A33 was much quieter. There must be photos somewhere of the old layout.
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Fluid Dynamics
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Re: M3 Junction 9 Improvements

Post by Fluid Dynamics »

Excuse me if my memory is wrong, but I thought pre 1990 the route split with a lane each for the A33 and A34 rather than a standard diverge. The A34 gained a lane right after the diverge. Before the M3 was extended south of Popham the A33 was definitely the major route, I remember that at that time not all the A34 had been improved, nor the M40 opened. In fact for many years the A34 dualling ended at the next GSJ at the top of the hill before the Sutton Scotney bypass opened.
Last edited by Fluid Dynamics on Thu Jul 04, 2019 12:54, edited 1 time in total.
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Stevie D
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Re: M3 Junction 9 Improvements

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RichardA35 wrote: Wed Jul 03, 2019 09:49
jackal wrote: Wed Jul 03, 2019 00:28It's a small thing, but I'm not keen on the gratuitous roundabout for accessing... HE's own depot!
Not really gratuitous - the access and egress must be available for all directions so the access road south of the roundabout is two way. The alternative would either be a "fast" side exit northbound to access the M3 or more likely a "left out" only leading south to a circumnavigation of the entire dumbbell to head back north onto the M3.
It still doesn't need a roundabout. A signalised T-junction running off vehicle sensors to allow traffic to turn right out of the depot would be less disruptive to traffic flow and would reduce the risk of regular users of the junction failing to anticipate a vehicle turning right out of the depot at the roundabout.
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Re: M3 Junction 9 Improvements

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Excuse me if my memory is wrong, but I thought pre 1990 the route split with a lane each for the A33 and A34 rather than a standard diverge. The A34 gained a lane right after the diverge. Before the M3 was extended south of Popham the A33 was definitely the major route, I remember that at that time not all the A34 had been improved, nor the M40 opened.
It may well have been. All I remember is that it was changed a few years after the M3 opened. The A34 certainly was quieter before the M40 opened and was partly S2 until after the M40. There must be official HCC photos in the Winchester Archive, will have to take a look.
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jervi
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Re: M3 Junction 9 Improvements

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It still doesn't need a roundabout. A signalised T-junction running off vehicle sensors to allow traffic to turn right out of the depot would be less disruptive to traffic flow and would reduce the risk of regular users of the junction failing to anticipate a vehicle turning right out of the depot at the roundabout.
At some point motorway regulations have to start, simply can be put into 3 options.
[*] if you have it when leaving the dumbbell then depot traffic would have to travel southwards along the road to the dumbbell, by the looks of things that but of road would be single carriageway, and I doubt their want to have a new motorway sliproad which is part two way traffic and with a roundabout on it.
[*] T-junction providing access to depot. Wouldn't need to be traffic light controlled though, no traffic would be crossing each other, only traffic joining if leaving the depot northbound. This would not provide any opportunity for non-motorway traffic to turn around, however could be adapted to provide some sort of provision. Kinda what you suggested, and tbh the most suitable option.
[*]What I'd guess the current designs show, regulations starting after the roundabout, which allows non-motorway traffic to turn around and better flow of traffic leaving the depot (but tbh no one cares about that part)
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Re: M3 Junction 9 Improvements

Post by jervi »

Just thought about it. Maybe the traffic on the roundabout gives way to traffic coming down from the dumbell. As long as it is clearly signed I'd imagine that's the best option?
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Re: M3 Junction 9 Improvements

Post by Richardf »

jervi wrote: Fri Jul 05, 2019 00:40 Just thought about it. Maybe the traffic on the roundabout gives way to traffic coming down from the dumbell. As long as it is clearly signed I'd imagine that's the best option?
If you had that setup, you might just as well have a T junction with part time signals. Goes against all the rules of driving roundabouts.
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Re: M3 Junction 9 Improvements

Post by ColinB »

I believe the new M3 slip road uses part of the existing A34 NB carriageway. For Access to the HE depot could they not retain the southern end of the existing A34 SB carriageway as a two way road that only leads to the depot.
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Re: M3 Junction 9 Improvements

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Here's my revised design, with access to the depot via a northbound lane drop. This removes the 'two access point' issue that Bryn mentioned.

M3 J9 depot revised - Copy.jpg

I still have a lane gain onto the northbound slip. As this is freeflow with no conflicts, and tiny volumes from the depot, I really don't see any safety issue. This is especially so compared to HE's proposed new roundabout, which introduces a severe deflection for the much higher volume of traffic using the slip road, as well as traffic conflicts where there should be none. (The existing roundabout in the depot remains a dog's dinner under both proposals, and is properly outside the scope of the scheme.)
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Re: M3 Junction 9 Improvements

Post by Glom »

Chris5156 wrote:
Bryn666 wrote: Tue Jul 02, 2019 22:50Spoiler: there's one going into Heathrow Terminal 5. The sky is still above it and yet to fall in...
That’ll be another one at Heathrow T5 then - there’s one already. Exit clockwise M25 at J14, and the T5 spur forms a right-hand exit from the sliproad, for some reason.
It is from a sliproad though. And that exit carries on for longer before hitting a junction than the "mainline" going to the A3113 roundabout.
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Re: M3 Junction 9 Improvements

Post by JammyDodge »

New consultation starts today
I grabbed this image from HE:SE on Facebook (the virtual consultation wasn't live yet). Seems to show the A33 separated from the A34 to mitigate weaving issues between Junction 9 and the diverge. Also, the dumbell has been dropped in favour of a "traditional" roundabout
192637725_4107234689315613_7533874141040598944_n.jpg
Ultimately looks very promising
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Re: M3 Junction 9 Improvements

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Seems to not have the link to it from the project page. But it is accessible here
https://highwaysengland.citizenspace.co ... lementary/

Fly through video - https://www.youtube.com/watch?v=bOijxUVkL9Y
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jackal
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Re: M3 Junction 9 Improvements

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The changes look really good on the whole. Closing the A33 junction and giving it a new route to reach J9 is a simple but effective way of removing weaving on the A34. The A33 is low volume and has no need of a freeflow connection to the strategic network.

I have a few suggestions for possible changes:

- I'm not sure why they have changed to a two bridge roundabout (with new bridges) from the previously planned dumbbell. There will be a massive reduction in traffic due to M3-A34 traffic bypassing the roundabout, and the dumbbell is surely cheaper.
- I really like the idea of using the abandoned A33 northbound carriageway as an NMU route, but why is it shown only as a footway on the plans? It would be perfect for a combined foot/cycleway.
- The roundabout for the HE depot still strikes me as inconvenient for everyone other than HE, and a waste of public funds. There's nothing wrong with the current access arrangements, but if HE really need a full access junction, at least make it a priority junction so A33 and northbound sliproad traffic doesn't have to brake and accelerate every time (with safety and CO2 implications) for what is fundamentally a glorified property access. This would also allow the current A34 northbound carriageway to be used as a foot/cycleway as it wouldn't have a roundabout protruding into it as under HE plans.
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Re: M3 Junction 9 Improvements

Post by Bryn666 »

Good that they've removed the A33 from the equation by relegating it, rightly, to a local road.

This now looks like a very good scheme, with walking (and I hope cycling???) considered as well by re-using the otherwise abandoned A33 fork for this.

I agree with Jackal's comments too (!).
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Re: M3 Junction 9 Improvements

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Bryn666 wrote: Thu May 27, 2021 10:29 I agree with Jackal's comments too (!).
:-o
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Re: M3 Junction 9 Improvements

Post by Bryn666 »

jackal wrote: Thu May 27, 2021 10:38
Bryn666 wrote: Thu May 27, 2021 10:29 I agree with Jackal's comments too (!).
:-o
To answer the roundabout question though, I'm guessing those two dreaded words "retail park" are to blame for going back to a gargantuan signal controlled two bridge than a cheaper dumbbell. I also imagine the Spitfire Link into Winchester will still attract a fair whack of traffic even though we shouldn't really be encouraging traffic to drive into a small city like this - whatever happened to the park and ride on the line of the old bypass?
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Re: M3 Junction 9 Improvements

Post by Herned »

Bryn666 wrote: Thu May 27, 2021 10:29 Good that they've removed the A33 from the equation by relegating it, rightly, to a local road.

This now looks like a very good scheme, with walking (and I hope cycling???) considered as well by re-using the otherwise abandoned A33 fork for this.

I agree with Jackal's comments too (!).
I agree, it looks a very good scheme. Cycling is specifically mentioned in the consultation materials, and is presumably the reason for the spiral ramp inside the roundabout, although I would bet that pedestrians will choose the direct line and not use that path
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Re: M3 Junction 9 Improvements

Post by jackal »

From the video I see they now only propose three lanes southbound through J9 (with a lane gain south of J9). If three lanes is enough I wonder if they really need to replace the bridges and mess with the existing junction at all.
Herned wrote: Thu May 27, 2021 11:54 I agree, it looks a very good scheme. Cycling is specifically mentioned in the consultation materials, and is presumably the reason for the spiral ramp inside the roundabout, although I would bet that pedestrians will choose the direct line and not use that path
Yes, there is a national cycle route running northeasterly through the junction, hence the spiral. My point is that the new NMU route running northwest from the junction to Kings Worthy is marked as footpath only when it would be perfect for cyclists.
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Re: M3 Junction 9 Improvements

Post by A303Chris »

Very impressive scheme, like the fact the A33 has been taken away from the A34, a relic from the original 1930's bypass.
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