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jackal wrote: ↑Wed Dec 09, 2020 15:05
Option A: £650m
Option B: £462m (renamed to option 1 for consultation)
Option C: £662m
Option D: £480m (renamed to option 2 for consultation)
From the option report, the only difference between option C and D is the GSJ at Farndon roundabout, yet it is nearly £200m more expensive. Yet the difference between options B and D, where there is also a GSJ/no-GSJ choice, is only £18m. Very strange...
Compared to D, C has three additional GSJs at NSLR, Farndon and Winthorpe:
B has a new bridge east of the A1. It also requires that the A617 is realigned and the A616 dualled. These additional elements explain why B (option 1) is similar in price to D (option 2).
It really is mad that they're considering a hamburger given the amount of work required - land take and environmental impact are actually higher than the GSJ.
jackal wrote: ↑Thu Dec 10, 2020 09:43
Compared to D, C has three additional GSJs at NSLR, Farndon and Winthorpe:
It really is mad that they're considering a hamburger given the amount of work required - land take and environmental impact are actually higher than the GSJ.
Oh right, thanks, my reading comprehension obviously needs some work! Odd that they combine all the expensive features in one option, rather than splitting up into more options with e.g. the whole route GSJ'd to the Winthorpe roundabout.
What is truly mad is putting in a new roundabout on the virtually new A46 dual carriageway, how is that allowed? And as per some of the proposed layouts in this thread, just put in one GSJ there with a link into Newark and then there is no need for a junction at Farndon at all
I don’t know the figures but I’d imagine that A46S<->A1N is a major flow here. It will be hard to provide a free flow for the southbound link but a northbound slip onto the A1 would be relatively easy although there may be a conflict with the railway at the point of merge.
Not GSJing Farndon and using the opportunity to tie in to the southern bypass is unforgivable, being the first at-grade junction encountered since Leicester.
Stick everything on a new expressway alignment to the south. Job done.
Yes, I agree and that's exactly what I would have done - this would then allow space for free flow slips for A1 > A46 traffic heading to Lincoln, and another pair for southbound A14 traffic to head off down the A17, leaving the existing junction and northern bypass for local traffic.
c2R wrote: ↑Thu Dec 10, 2020 13:40
Yes, I agree and that's exactly what I would have done - this would then allow space for free flow slips for A1 > A46 traffic heading to Lincoln, and another pair for southbound A14 traffic to head off down the A17, leaving the existing junction and northern bypass for local traffic.
As a local resident I can see the logic of making the new southern perimeter road a dual carriageway where there is level land and no need to raise the carriageway on banks. Surely this must be a lower cost solution even with extra bridges!! Has anyone studied this?
c2R wrote: ↑Thu Dec 10, 2020 13:40
Yes, I agree and that's exactly what I would have done - this would then allow space for free flow slips for A1 > A46 traffic heading to Lincoln, and another pair for southbound A14 traffic to head off down the A17, leaving the existing junction and northern bypass for local traffic.
As a local resident I can see the logic of making the new southern perimeter road a dual carriageway where there is level land and no need to raise the carriageway on banks. Surely this must be a lower cost solution even with extra bridges!! Has anyone studied this?
The consultation document gives a wooly sort of reply on this, saying that the newly constructed road is essentially rubbish and not suitable for strategic traffic, so a new alignment would be required, and that the additional distance involved would cause enough traffic not to divert so that congestion and delay would still feature on the northern bypass.
I'm wondering whether they might be better off not bothering and using the money more effectively on something else.
If £400 to £600 million would transform this bit of the A46 into a proper future-proofed up-to-standard fully GSJ-ed expressway (if we can still use that term), I think that might be money well spent. But this has the feel of a very expensive and probably temporary sticking plaster.
I appreciate that the site/terrain makes things difficult but even so!
£460m for four miles of predominantly at-grade dual carriageway is pretty mindblowing. That's what option 1 would get, and yes, I'd prefer they didn't bother.
Ultimately though I don't think they can just give up on the Newark bypass when it's such a short and obvious bottleneck on an 80 mile cross country route that is otherwise entirely dual carriageway. Nor, with the best will in the world, are alternative routings viable (e.g., a route around the south and east of Newark would be 50% longer). It should also be remembered that the new roundabout is part of the NSLR, and withdrawing the present scheme won't stop that from happening - quite the contrary.
So I'm still hoping they come up with a version of option 2 that is less of a bodge around Farndon. It will be expensive, but that's just where we are with a lot of the current schemes - the difficult bits are generally left until last (see also the A417 Air Balloon and A303/A358 upgrades). The high cost per mile can be justified as long as the standard is sufficient to realise the full potential of the much longer overall route.
If there isn't enough money for making the route to expressway standards (either on the current or alternative alignment), then a less expensive plaster would be just a free flow A46 fly over of the A1. In other words the Eastern end of Option 1, either as a single or dual carriageway. Maybe put that new DMRB standard for single carriageway GSJ. http://jervi.uk/stuff/newark4.png
It greatly improve A46 journey times, and reduce traffic at the dumbell roundabouts, freeing up capacity for the A17 and A1 slip roads.
I'd like to see the early 00s filter lane at the western roundabout restored.
Perhaps this was removed due to trouble with the lane dropping just off the roundabout but there would be alternative arrangements that fix that (e.g., have the filter lane merge or give way rather than lane gain).
While they're at it they could put in a filter at the same roundabout onto the A1 nb, though that one requires more than paint.
The M40 J9 pinchpoint scheme is the poster boy for bad practice in this respect - £7.23m spent for a huge increase in collisions and average 12 second increase in journey time. Monetised losses from the scheme were £2.7m in the first year (-£1.69m from safety, -£1.01m from journey time). Extend that over 30 years and you have a beefy -11.2 BCR (i.e., £11 lost for every £1 spent). That's not a pinchpoint; that's a pinchpoint.
What are the forecasts for the two options as regards the dangerous queueing of traffic that is leaving the A1 back onto the main carriageway of the A1? This can sometimes be a problem now, I believe. If the A46 is freeflow through the junction, does that eliminate the problem of queues back onto the A1?
By the way, whenever I'm travelling on the A1 from the north to get onto the A17 towards Sleaford I always skip the Winthorpe junction and go down to the next exit to use the old A17 through Coddington. There's never any delay getting safely off the A1 there.
Simon_GNR wrote: ↑Fri Dec 11, 2020 17:14
What are the forecasts for the two options as regards the dangerous queueing of traffic that is leaving the A1 back onto the main carriageway of the A1? This can sometimes be a problem now, I believe. If the A46 is freeflow through the junction, does that eliminate the problem of queues back onto the A1?
By the way, whenever I'm travelling on the A1 from the north to get onto the A17 towards Sleaford I always skip the Winthorpe junction and go down to the next exit to use the old A17 through Coddington. There's never any delay getting safely off the A1 there.
Thats clearly a rat run they wanted most people to avoid, but hey, it makes sense.
As for the queueing, it depends. I'm actually not sure which traffic flows are actually more dominant here. There's so much going off after all (Last time I went through it was A46 from A6097, round the bypass, onto A17 both ways). But you can say A46 onto A1 (Any combination) or even A46-A46 could be equally well used.
I guess the possibility of removing A46-A46 from the two islands might make the queueing easier because it's a movement which doesn't interact with the junctions at all.
C, E flat and G go into a bar. The barman says "sorry, we don't serve minors". So E flat walks off, leaving C and G to share an open fifth between them.
Never argue with an idiot. They will bring you down to their level and beat you with experience.
Simon_GNR wrote: ↑Fri Dec 11, 2020 17:14
By the way, whenever I'm travelling on the A1 from the north to get onto the A17 towards Sleaford I always skip the Winthorpe junction and go down to the next exit to use the old A17 through Coddington. There's never any delay getting safely off the A1 there.
Thats clearly a rat run they wanted most people to avoid, but hey, it makes sense.
As for the queueing, it depends. I'm actually not sure which traffic flows are actually more dominant here. There's so much going off after all (Last time I went through it was A46 from A6097, round the bypass, onto A17 both ways). But you can say A46 onto A1 (Any combination) or even A46-A46 could be equally well used.
I guess the possibility of removing A46-A46 from the two islands might make the queueing easier because it's a movement which doesn't interact with the junctions at all.
It's a rat run everyone does, except HGVs since there is a 7.5t limit on the old A17.
It is to note there is VMS on the approach to the junction on the A1, which can warn drivers of traffic backing onto the main carriageway, but the slip roads off the A1 really ought to be longer and/or segregated, there is plenty of room under the bridge.
Simon_GNR wrote: ↑Fri Dec 11, 2020 17:14
What are the forecasts for the two options as regards the dangerous queueing of traffic that is leaving the A1 back onto the main carriageway of the A1? This can sometimes be a problem now, I believe. If the A46 is freeflow through the junction, does that eliminate the problem of queues back onto the A1?
By the way, whenever I'm travelling on the A1 from the north to get onto the A17 towards Sleaford I always skip the Winthorpe junction and go down to the next exit to use the old A17 through Coddington. There's never any delay getting safely off the A1 there.
Thats clearly a rat run they wanted most people to avoid, but hey, it makes sense.
As for the queueing, it depends. I'm actually not sure which traffic flows are actually more dominant here. There's so much going off after all (Last time I went through it was A46 from A6097, round the bypass, onto A17 both ways). But you can say A46 onto A1 (Any combination) or even A46-A46 could be equally well used.
I guess the possibility of removing A46-A46 from the two islands might make the queueing easier because it's a movement which doesn't interact with the junctions at all.
I also go through Coddington - as does anyone not in an HGV I think.... I also doubt that A46-A46 is the second most dominant flow at the junction (other than A1-A1). Are there any statistics on journey start and endpoints buried away in the documents that anyone has seen?
jackal wrote: ↑Thu Dec 10, 2020 20:04£460m for four miles of predominantly at-grade dual carriageway is pretty mindblowing. That's what option 1 would get, and yes, I'd prefer they didn't bother.
I don't wish to be a broken record, but when you put it in those terms, it does remind me that this idea to spend half a billion pounds on four miles of crap dual carriageway is from the same people who propose to spend quarter of a billion pounds replacing a signalised three-level roundabout interchange with a signalised three-level roundabout interchange.
I can't believe I've only just stumbled upon this, it's only because a colleague mentioned the plans were out for the bypass that I thought I should check here...
I'm amazed that the plans to join up the Newark southern link road to a flat roundabout are actually being entertained, and that it looks as though Farndon Roundabout is staying. I'm even more amazed though, that the A1/A46 junction is staying exactly as is, considering the numerous issues with it, notably traffic consistently queuing back on to the mainline A1, and how difficult it is to pull out having turned off the A1 southbound - I usually want the A17 so always go via Coddington like everyone else below 7.5t.
I posted on the other thread - it may be worth merging the two by the way, about remodelling the A1/A46 junction - I still think doing something similar would have much more of a benefit than the freeflow link that just crashes into flat roundabouts anyway. Not very SABRE of me I know to suggest not having freeflow, but I can't understand how the A1/A46 junction can remain as it is. I believe a lot of A46 traffic wants the A1 rather than to carry on using the A46 in either direction, I haven't any figures to back up that assumption but would be interested to see some.