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Bryn666 wrote:My own view on this is the HA should finish the A428 dualling, and split A1 North and A1 South traffic. Furthermore, by improving the full A428 corridor (this requires widening the A1/A428 multiplex to D3, and GSJing Black Cat), you've just created a brand new A1-M1 link to shadow the existing A14.
Can you name any major journeys that would shift from A14 to A421/A428 if only they did the upgrades you mention? I can't think of any.
In my view, upgrading the A421/A428 would take away a negligible amount of the A14 traffic between the A1 and M11, so I don't think it's any alternative to upgrading the A14.
Have you got £1.3bn spare?
There are clear aspirations to complete a new corridor from Cambridge to Milton Keynes as otherwise the A428 would not have just been improved. The HA don't dual roads unless there's a sound business case for doing so, so clearly this corridor is valuable to them. So finish dualling it, you might just encourage traffic from Felixstowe to avoid the ex-A604 section of A14 altogether that way.
As for the A14 improvements, we should be talking about an M11 extension to the A1(M), retaining the existing A14 for local traffic - there are new 'towns' planned along that corridor after all.
Bryn Terminally cynical, unimpressed, and nearly Middle Age already. She said life was like a motorway; dull, grey, and long.
Bryn666 wrote:There are clear aspirations to complete a new corridor from Cambridge to Milton Keynes as otherwise the A428 would not have just been improved. The HA don't dual roads unless there's a sound business case for doing so, so clearly this corridor is valuable to them. So finish dualling it, you might just encourage traffic from Felixstowe to avoid the ex-A604 section of A14 altogether that way.
From Felixstowe to where? I know it feels like the A421/A428 corridor should be an alternative to the A14, as they both run roughly parallel, but there's virtually no overlap in the journeys they can plausibly serve.
I'm perfectly happy with the idea that A421/A428 should be upgraded in its own right. I'm just pointing out that it often gets brought up in discussions about the A14 west of Girton, which it actually has nothing to do with. For example:
Bryn666 wrote:The replacement Wolvercote Viaduct on the A34 shows you can do these huge repairs whilst retaining D2, so it'd be painful but not catastrophic to replace it. This should be done anyway was I think removing the Huntingdon Bypass altogether will screw over the town in the long-run as the new road will be too far away too attract traffic from the town.
My own view on this is the HA should finish the A428 dualling, and split A1 North and A1 South traffic. Furthermore, by improving the full A428 corridor (this requires widening the A1/A428 multiplex to D3, and GSJing Black Cat), you've just created a brand new A1-M1 link to shadow the existing A14.
These are relatively low cost fixes that provide medium-term capacity whilst a full M11 extension to Alconbury is designed.
From Felixstowe to where? I know it feels like the A421/A428 corridor should be an alternative to the A14, as they both run roughly parallel, but there's virtually no overlap in the journeys they can plausibly serve.
Well for those long distance journeys the A428/A421/M1 forms the other side of a box which could be a strategic alternative to the overloaded bits of the A14. Yes, it's longer, and not quite as direct, but if we're never going to actually fix the A14 perhaps some kind of traffic split could be carried out. Ultimately the A421 improvements need to go west to the M40. But that means fixing M40 J10...
The majority of the cost of the new A14 scheme is fixing the junctions along the way - is there a low cost alternative to rebuilding Girton that eliminates the A14 TOTSO and provides full access between A14 and M11?
Bryn Terminally cynical, unimpressed, and nearly Middle Age already. She said life was like a motorway; dull, grey, and long.
Bryn666 wrote:The majority of the cost of the new A14 scheme is fixing the junctions along the way - is there a low cost alternative to rebuilding Girton that eliminates the A14 TOTSO and provides full access between A14 and M11?
I think rebuilding Girton would be a minor expense relative to the cost of making the A428 route fit for A14 traffic, if that's what you have in mind. You'd have to (a) widen the existing dualled parts of the A428 to at least D3, (b) build a new route north of St Neots to the A1, (c) widen the A1, and (d) put in some freeflow at the A1/A14 junction.
I know you're proposing something more small scale, but I don't see how giving a better A428 option will attract any A14 traffic unless there is a way for it to get back to the M6, which is where most of the long distance traffic is heading. Going via M1 J13 is just too much of a long way round to be credible even if it was significantly upgraded. Traffic would stick to the A14 unless you put traffic calming measures on it.
In any case, and as I mentioned, Girton is a lower priority than building the offline section of the £1.3bn plan. Building that section alone wouldn't cost much, if any, more than the A428 dualling and associated A1 widening and Black Cat upgrade that you mentioned, and it would bring more benefits in my opinion.
As Jackal mentioned, upgrading the A428 alone would solve nothing as it would still be a D2 carrying north-south and east-west traffic so we would be back to square one, not to mention the extra distance involved to go via St Neots.
A more workable solution would be to continue the D2 A428 northwestwards from Caxton to join the A14 near Ellington. The overall distance between Girton and Ellington would hardly be different to the existing A14 and this would remove the need to alter Girton as the A14 would then be pointing the right way. Something would still need to be done about the viaduct at Huntingdon to cater from M11-Peterborough traffic but at least that and A14 traffic would be kept entirely separate.
How would you like your grade separations, Sir? Big and complex.
If you build a new D2AP road the seven or eight miles from Caxton Gibbet to Black Cat and ensure it is grade separated at both ends then you have an expressway with no substandard junctions or left turns all the way from the A14 at Cambridge to the M1 at Milton Keynes.
I would have thought that would make A428/A421/M1/M6 quite an attractive alternative to the A14 west of Cambridge at very little cost. If I recall the A14 west of the A1 is not exactly expressway standard with various carriageway crossing right turns and also has delaying totso's at Cambridge, Huntingdon and the M6 junction, not to mention the unfortuntate lack of online grade separation at the A1 roundabout.
In the long term, extention of the M11 to the M6 as D3M and renaming the whole lot the M6 London to Glasgow Motorway is the logical thing to do.
A303Paul wrote:If you build a new D2AP road the seven or eight miles from Caxton Gibbet to Black Cat and ensure it is grade separated at both ends then you have an expressway with no substandard junctions or left turns all the way from the A14 at Cambridge to the M1 at Milton Keynes.
I would have thought that would make A428/A421/M1/M6 quite an attractive alternative to the A14 west of Cambridge at very little cost. If I recall the A14 west of the A1 is not exactly expressway standard with various carriageway crossing right turns and also has delaying totso's at Cambridge, Huntingdon and the M6 junction, not to mention the unfortuntate lack of online grade separation at the A1 roundabout.
Precisely - the A428/A421 corridor won't be right for all A14 traffic west of Cambridge, but to me it seems obvious that the gap should be filled anyway; with that done, the true underlying level of remaining demand on the A14 would become clearer and upgrades, if any, easier to assess. As you say, west of Cambridge, the dualled sections of A428/A421 are of a much higher standard than the A14.
I suspect that one obstacle is the question of what to do at Black Cat - would it be a good idea to build a fancy interchange with the A1 there if there is still a chance that the relevant section of A1 might be upgraded, perhaps on a different alignment? If funds were limited, which route should be the priority to get the benefit from grade separation? Personally, I'd say A428/1.
If an improved A421/8 does become a viable alternative to the A14 as an east coast to M6 route, do we not then run the risk of overcrowding on the M1 between J13 and 19?.
But I seem to be going along with the view that the A421/8 (give it a single number, please!) deserves upgrading to D2 throughout on its own merits, regardless of whether it inadvertantly becomes an A14 relief road.
skiddaw05 wrote:If an improved A421/8 does become a viable alternative to the A14 as an east coast to M6 route, do we not then run the risk of overcrowding on the M1 between J13 and 19?.
But I seem to be going along with the view that the A421/8 (give it a single number, please!) deserves upgrading to D2 throughout on its own merits, regardless of whether it inadvertantly becomes an A14 relief road.
I think it would depend on the time of main flows.
If the main westbound flow is in the morning with eastbound traffic heavy in the evening, then the M1 would be fine, but if the other way round it would clash with the rush hour traffic to/from London.
roadtester wrote:
I suspect that one obstacle is the question of what to do at Black Cat - would it be a good idea to build a fancy interchange with the A1 there if there is still a chance that the relevant section of A1 might be upgraded, perhaps on a different alignment? If funds were limited, which route should be the priority to get the benefit from grade separation? Personally, I'd say A428/1.
The best option would be to make the A421/A428 freeflow throughout with a simple roundabout or dumbbell GSJ with the A1. The A1 has at-grade roundabouts in the area already so another one won't make any difference. If and when the A1 is upgraded a new junction can be added to the A421/A428 whereby the upgraded A1 is bridged over or under it and some slips added. Anyway, a temporary junction would have to favour the A421/A428 as there's no point having an A1 flyover or underpass if there's a chance of it becoming redundant in the future such as what happened at Kirk Deighton.
How would you like your grade separations, Sir? Big and complex.
I've got this delight to come three times next season if I choose to go to the away games at Doncaster, Hull and Middlesbrough, as for some reason our coach managers choose to go A23-M23-M25-M11-A14-A1 for East Coast games, rather than using the M1 and M18 before heading north (I don't know which would be quicker, but I would probably go the western route on the M25 and then take the M1 and M18). We had a fairly easy run to Hartlepool last season on that route, but I find the A1 between Peterborough and Doncaster so featureless, and the non-motorway D2 sections are not especially comfortable in a coach.
So what are they going to do about the Huntington viaduct? I thought that was coming to the end of its life or something to that effect.
Still, this is bad news. I do agree with you, though. Why spend billions of pounds on a ministers wet dream when you could use that money to improve bottlenecks like this. In fact, with the money they want to spend on HS2 they could make the section between the A1 and M11 D3M (just, if they fiddle about with layouts and stuff)!
I don't like the feeling of them looking for a "cost effective" solution to the problem. My guess is that it will mean lots of roundabouts and a 50 limit!
geo449 wrote:
I don't like the feeling of them looking for a "cost effective" solution to the problem. My guess is that it will mean lots of roundabouts and a 50 limit!
How about just not 'gold plating' it, i.e. slap some tarmac down on a field, and not faff about with ATM, VMS, public enquiries etc etc.
A303Paul wrote: ↑Wed Mar 02, 2011 18:06
In the long term, extention of the M11 to the M6 as D3M and renaming the whole lot the M6 London to Glasgow Motorway is the logical thing to do.