A428 Black Cat - Caxton Gibbet improvement

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jackal
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Re: Black Cat - Cambourne rumour?

Post by jackal »

Roadiecambs wrote: Thu Jun 25, 2020 15:44
jackal wrote: Thu Jun 25, 2020 11:41
Roadiecambs wrote: Thu Jun 25, 2020 09:46
I am not really clear though that Option A was any better. Sure, it provided a freeflow link for A1 SB to A421 WB, a very busy movement, but at the expense of all the other movements, which would have had very circuitous routes via two small dumbbell roundabouts to get through the junction. Bear in mind that, e.g. A428 WB to A1 SB (and A1NB to A428 EB) is likely to have increased movement with all the Wintringham development on the southern edge of St Neots. Plus it is true that A1 SB to A428 WB will become a less dominant movement once the A428 is rerouted. I agree that something more ambitious (4 level stack etc) would have been the gold-plated solution, but given the limited budget and the need to provide local access I actually think the stackabout is the best compromise here. I doubt there will be any major traffic problems until after Buckden roundabout is removed, for which there are no plans at all.
Option A is better for movements on the roundabouts as well. Going around a couple of uncongested dumbells is easy compared to navigating a huge, congested gyratory that's signalised from day 1 as this is confirmed to be (see general arrangement). If you're right that WB to SB and NB to EB will become busier movements the roundabout will require further signalisation, and probably extra 'stacking space', as these movements conflict with SB to WB. As Option A freeflows SB to WB there is far less traffic on the roundabouts and signalisation is unnecessary.
Sorry, but I don't see how putting all the movements apart from A1SB-A421WB on two tight roundabouts is in any way an improvement over a large stackabout (bear in mind that A421EB to A1NB has a freeflow lane in option C)
Option A does not put "all the movements apart from A1SB-A421WB on two tight roundabouts". It has all the freeflow movements of option C, and in addition A1SB-A421SB is freeflow, i.e. it freeflows all the strategic movements.
There are a large number of conflicting movements in the dumbbell arrangement, and far less queueing space, so I have no doubt that the dumbbell roundabouts would also have to be signalised from day one too.

For example, in Option A, on the southern roundabout, A1NB to A428EB conflicts with A1SB to A428EB. On the northern roundabout, A421EB to A1SB (admittedly a small movement) conflicts with A1NB to A428EB and A1Sb to A428EB. At least in the stackabout there is plenty of queueing space, and the roundabout is large and wide, which certainly can't be said for the dumbbell option.
There are thousands of roundabouts all over the country that link small towns and villages like this just fine with no signals. What roundabouts don't cope well with, as proven time and time again, are heavy movements between strategic roads like A1SB to A421.

The next bit is fundamental to understanding the junction: the likes of A1NB to A428 or A1SB to A428 may be between strategic roads but they have zero strategic value and were not even provided in Option B. The only turning movements of importance are between A1N and A421, and the stackabout makes a terrible mess of half of them.

"The roundabout is large and wide" is just a beautiful summary of British system interchange design philosophy. I'm having that.
Last edited by jackal on Thu Jun 25, 2020 16:54, edited 2 times in total.
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Re: Black Cat - Cambourne rumour?

Post by trickstat »

jackal wrote: Thu Jun 25, 2020 16:37
Roadiecambs wrote: Thu Jun 25, 2020 15:44
jackal wrote: Thu Jun 25, 2020 11:41
Option A is better for movements on the roundabouts as well. Going around a couple of uncongested dumbells is easy compared to navigating a huge, congested gyratory that's signalised from day 1 as this is confirmed to be (see general arrangement). If you're right that WB to SB and NB to EB will become busier movements the roundabout will require further signalisation, and probably extra 'stacking space', as these movements conflict with SB to WB. As Option A freeflows SB to WB there is far less traffic on the roundabouts and signalisation is unnecessary.
Sorry, but I don't see how putting all the movements apart from A1SB-A421WB on two tight roundabouts is in any way an improvement over a large stackabout (bear in mind that A421EB to A1NB has a freeflow lane in option C)
Option A does not put "all the movements apart from A1SB-A421WB on two tight roundabouts". It has all the freeflow movements of option C, and in addition A1SB-A421SB is freeflow, i.e. it freeflows all the strategic movements.
There are a large number of conflicting movements in the dumbbell arrangement, and far less queueing space, so I have no doubt that the dumbbell roundabouts would also have to be signalised from day one too.

For example, in Option A, on the southern roundabout, A1NB to A428EB conflicts with A1SB to A428EB. On the northern roundabout, A421EB to A1SB (admittedly a small movement) conflicts with A1NB to A428EB and A1Sb to A428EB. At least in the stackabout there is plenty of queueing space, and the roundabout is large and wide, which certainly can't be said for the dumbbell option.
There are thousands of roundabouts all over the country that link small towns and villages like this just fine with no signals. What roundabouts don't cope well with, as proven time and time again, are heavy movements between strategic roads like A1SB to A421.

The next bit is fundamental to understanding the junction: the likes of A1NB to A428 or A1SB to A428 may be between strategic roads but they have zero strategic value and were not even provided in Option B. The only turning movements of importance are between A1N and A428, and the stackabout makes a terrible mess of half of them.

"The roundabout is large and wide" is just a beautiful summary of British system interchange design philosophy. I'm having that.
Do you mean A1N and A421?
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Re: Black Cat - Cambourne rumour?

Post by Roadiecambs »

jackal wrote: Thu Jun 25, 2020 16:37
Roadiecambs wrote: Thu Jun 25, 2020 15:44
jackal wrote: Thu Jun 25, 2020 11:41
Option A is better for movements on the roundabouts as well. Going around a couple of uncongested dumbells is easy compared to navigating a huge, congested gyratory that's signalised from day 1 as this is confirmed to be (see general arrangement). If you're right that WB to SB and NB to EB will become busier movements the roundabout will require further signalisation, and probably extra 'stacking space', as these movements conflict with SB to WB. As Option A freeflows SB to WB there is far less traffic on the roundabouts and signalisation is unnecessary.
Sorry, but I don't see how putting all the movements apart from A1SB-A421WB on two tight roundabouts is in any way an improvement over a large stackabout (bear in mind that A421EB to A1NB has a freeflow lane in option C)
Option A does not put "all the movements apart from A1SB-A421WB on two tight roundabouts". It has all the freeflow movements of option C, and in addition A1SB-A421SB is freeflow, i.e. it freeflows all the strategic movements.
There are a large number of conflicting movements in the dumbbell arrangement, and far less queueing space, so I have no doubt that the dumbbell roundabouts would also have to be signalised from day one too.

For example, in Option A, on the southern roundabout, A1NB to A428EB conflicts with A1SB to A428EB. On the northern roundabout, A421EB to A1SB (admittedly a small movement) conflicts with A1NB to A428EB and A1Sb to A428EB. At least in the stackabout there is plenty of queueing space, and the roundabout is large and wide, which certainly can't be said for the dumbbell option.
There are thousands of roundabouts all over the country that link small towns and villages like this just fine with no signals. What roundabouts don't cope well with, as proven time and time again, are heavy movements between strategic roads like A1SB to A421. The likes of A1NB to A428 or A1SB to A428 may be between strategic roads but they have zero strategic value and were not even included in Option B.

"The roundabout is large and wide" is just a beautiful summary of British system interchange design philosophy. I'm having that.
We'll have to agree to disagree here. I simply don't think that A1SB to A421WB is the only significant movement in this junction, and that all the other movements should be sacrificed as they are not, in some vaguely defined way, "strategic". Indeed the A1SB to A421WB movement is likely to become relatively less important (less strategic?), and the other movements are likely to become relatively more important, given the realignment of the A421/428 to freeflow through the junction, plus all the additional development (referenced upthread) that's happening in the A421/428 corridor that's likely to want to use the A1 NB and SB.

There's been some appalling examples of dumbbell designs causing total gridlock between strategic routes - the M40/A43 being the most obvious, when it was still a single carriageway (as Option A was planned here), so I am highly dubious that it's only stackabouts that generate problems. As I said above, in a fantasy world I would love if this was a free-flowing stack, but in the world we live in of confined budgets, this just ain't going to happen. So the stackabout (to me at least) seems the correct compromise.
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Re: Black Cat - Cambourne rumour?

Post by jackal »

trickstat wrote: Thu Jun 25, 2020 16:51 Do you mean A1N and A421?
Thanks, yes I do. Now edited.
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Re: Black Cat - Cambourne rumour?

Post by jackal »

Roadiecambs wrote: Thu Jun 25, 2020 16:54
jackal wrote: Thu Jun 25, 2020 16:37
Roadiecambs wrote: Thu Jun 25, 2020 15:44
Sorry, but I don't see how putting all the movements apart from A1SB-A421WB on two tight roundabouts is in any way an improvement over a large stackabout (bear in mind that A421EB to A1NB has a freeflow lane in option C)
Option A does not put "all the movements apart from A1SB-A421WB on two tight roundabouts". It has all the freeflow movements of option C, and in addition A1SB-A421SB is freeflow, i.e. it freeflows all the strategic movements.
There are a large number of conflicting movements in the dumbbell arrangement, and far less queueing space, so I have no doubt that the dumbbell roundabouts would also have to be signalised from day one too.

For example, in Option A, on the southern roundabout, A1NB to A428EB conflicts with A1SB to A428EB. On the northern roundabout, A421EB to A1SB (admittedly a small movement) conflicts with A1NB to A428EB and A1Sb to A428EB. At least in the stackabout there is plenty of queueing space, and the roundabout is large and wide, which certainly can't be said for the dumbbell option.
There are thousands of roundabouts all over the country that link small towns and villages like this just fine with no signals. What roundabouts don't cope well with, as proven time and time again, are heavy movements between strategic roads like A1SB to A421. The likes of A1NB to A428 or A1SB to A428 may be between strategic roads but they have zero strategic value and were not even included in Option B.

"The roundabout is large and wide" is just a beautiful summary of British system interchange design philosophy. I'm having that.
We'll have to agree to disagree here. I simply don't think that A1SB to A421WB is the only significant movement in this junction, and that all the other movements should be sacrificed as they are not, in some vaguely defined way, "strategic". Indeed the A1SB to A421WB movement is likely to become relatively less important (less strategic?), and the other movements are likely to become relatively more important, given the realignment of the A421/428 to freeflow through the junction, plus all the additional development (referenced upthread) that's happening in the A421/428 corridor that's likely to want to use the A1 NB and SB.

There's been some appalling examples of dumbbell designs causing total gridlock between strategic routes - the M40/A43 being the most obvious, when it was still a single carriageway (as Option A was planned here), so I am highly dubious that it's only stackabouts that generate problems. As I said above, in a fantasy world I would love if this was a free-flowing stack, but in the world we live in of confined budgets, this just ain't going to happen. So the stackabout (to me at least) seems the correct compromise.
Why do you keep strawmaning with this "A1SB to A421WB is the only significant movement" stuff? Obviously the reverse movement and mainlines are significant, as I've repeatedly stated.

M40/A43 is precisely the "use roundabouts for strategic movements" approach that I am criticising and you are endorsing.

If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
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Re: Black Cat - Cambourne rumour?

Post by KeithW »

jackal wrote: Thu Jun 25, 2020 16:37
There are thousands of roundabouts all over the country that link small towns and villages like this just fine with no signals. What roundabouts don't cope well with, as proven time and time again, are heavy movements between strategic roads like A1SB to A421.

The next bit is fundamental to understanding the junction: the likes of A1NB to A428 or A1SB to A428 may be between strategic roads but they have zero strategic value and were not even provided in Option B. Likewise with A421EB to A1SB and A1NB to A421 WB, which are virtually U-turns and probably only included as a side effect of providing local access. HE had really quite an easy job, as the only turning movements of importance are between A1N and A428, but the stackabout makes a terrible mess of half of them.

"The roundabout is large and wide" is just a beautiful summary of British system interchange design philosophy. I'm having that.
The basic problem from the moment the new A421 opened was that at the Black Cat you had a high volume of traffic coming down the A421 and ALL of it was turning either southbound or northbound. When you look at it farther its clear that a lot of the traffic turning north from the A421 was in fact destined for the A428/A14. Its clear that simply making the A1 and A421/A428 free flow should be a significant improvement. Its not ideal but then what realistic option was.

For the record the queues on the A1 northbound to the A421 westbound and from the A421 for the A1 northbound were the worst every time I hit it to the extent that I would turn southbound off the A421 , get off the A1 at Tempsford and cut up the unclassified road to Little Barford to pick up the A428

I rarely hit a significant delay from the A1 southbound to the A421 westbound. In fact the Google aerial view shows the typical state.
https://www.google.co.uk/maps/@52.18407 ... a=!3m1!1e3
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Re: Black Cat - Cambourne rumour?

Post by KeithW »

jackal wrote: Thu Jun 25, 2020 17:15 If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
Turns from the A1 onto the A428 take you to Cambridge and its Science Park and via the A14/A11 to Norwich, Ispwich and Felixstowe. If you are heading in that direction from a point north of Welwyn the only alternative is the A505 which is a pretty poor west of Royston. Sounds pretty strategic to me.
Last edited by KeithW on Thu Jun 25, 2020 17:44, edited 1 time in total.
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Re: Black Cat - Cambourne rumour?

Post by thatapanydude »

It would be interesting to know is the stack-bout is cheaper than the dumbbell option?

My take is that the A1 SB to A421 W flow won't be that busy as the turning movements prior are catered by the flyover. I would also add the flows from A1 South to A421 East will pick up as lots of traffic before who used to use the old B1043 or B1040 to cut to the A428 towards Camrbridge (including myself) will now use the A421 joining at Black Cat.
KeithW wrote: Thu Jun 25, 2020 13:33
This junction is literally lethal. Traffic along the B1040 (including me) had to make a right turn across a busy road with vehicles doing 60 mph.
https://www.google.co.uk/maps/@52.22196 ... 312!8i6656

Not to mention the Croxton junction
https://www.google.co.uk/maps/@52.22483 ... 312!8i6656


As someone who has been through this junction on many a time, I concur its lethal and very nervous turning from the B1040 or further up at Eltisley to the A428 Cambridge bound.

Often I wonder whether its better to just join the "daily" queue from St Neots on A428 just to avoid cutting the corner (just to this horrific mess) as many do from East Beds.

A few finals points would be I would guess the B1040 will now be renembered to take over the section at Eltisley where its currently shared alongside the A428 and I also hope the A421 and A1 gets some tech with MS3 and MS4, both are desperately needed it.
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Re: Black Cat - Cambourne rumour?

Post by Roadiecambs »

jackal wrote: Thu Jun 25, 2020 17:15
Roadiecambs wrote: Thu Jun 25, 2020 16:54
jackal wrote: Thu Jun 25, 2020 16:37
Option A does not put "all the movements apart from A1SB-A421WB on two tight roundabouts". It has all the freeflow movements of option C, and in addition A1SB-A421SB is freeflow, i.e. it freeflows all the strategic movements.

There are thousands of roundabouts all over the country that link small towns and villages like this just fine with no signals. What roundabouts don't cope well with, as proven time and time again, are heavy movements between strategic roads like A1SB to A421. The likes of A1NB to A428 or A1SB to A428 may be between strategic roads but they have zero strategic value and were not even included in Option B.

"The roundabout is large and wide" is just a beautiful summary of British system interchange design philosophy. I'm having that.
We'll have to agree to disagree here. I simply don't think that A1SB to A421WB is the only significant movement in this junction, and that all the other movements should be sacrificed as they are not, in some vaguely defined way, "strategic". Indeed the A1SB to A421WB movement is likely to become relatively less important (less strategic?), and the other movements are likely to become relatively more important, given the realignment of the A421/428 to freeflow through the junction, plus all the additional development (referenced upthread) that's happening in the A421/428 corridor that's likely to want to use the A1 NB and SB.

There's been some appalling examples of dumbbell designs causing total gridlock between strategic routes - the M40/A43 being the most obvious, when it was still a single carriageway (as Option A was planned here), so I am highly dubious that it's only stackabouts that generate problems. As I said above, in a fantasy world I would love if this was a free-flowing stack, but in the world we live in of confined budgets, this just ain't going to happen. So the stackabout (to me at least) seems the correct compromise.
Why do you keep strawmaning with this "A1SB to A421WB is the only significant movement" stuff? Obviously the reverse movement and mainlines are significant, as I've repeatedly stated.

M40/A43 is precisely the "use roundabouts for strategic movements" approach that I am criticising and you are endorsing.

If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
OK I am really sorry if you thought my tone was offensive or "strawmanning" here. That certainly was not the intention so I do apologise profusely if that's how it came across.

I am just quite unclear why you think there will be a major traffic issue here. If, as you suggest, all the "non-strategic" turns (A1NB-A428WB etc.) are negligible anyway, then basically either solution (A or C) will work absolutely fine. A will work fine because the "strategic movement" is separated entirely, but the stackabout will also work fine as there will be effectively no conflict on the roundabout. As I said upthread, it's my view that the A1SB to A421WB will become relatively less used, and that the others will become relatively more used, given the development in the corridor. Therefore, I feel it's better to have some decent provision for the other movements (rather than two tight dumbbell roundabouts), even if it's slightly at the cost of the "strategic movement". In both options, A421EB to A1N is freeflow anyway.
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Re: Black Cat - Cambourne rumour?

Post by NICK 647063 »

I’ve not read the whole thread so apologies if this question has already been asked but is the plan to number the new road the A421, I remember the A428 getting renumbered from the Bedford bypass to black cat when it used to pass through Great Barford, it would seem pointless doing that if the A421 was to simply flow into the A428 at the new Black cat interchange, having the whole thing numbered A421 surely makes sense.

Also looking at the plans quite a bit of work is to be done through Wyboston, sadly the lovely thatched cottage will be under the A1, it looks like all property access will be via new service roads with the A1 still cutting through Wyboston, surely a western bypass for Wyboston wouldn’t be too hard, looking at satellite view you can fit it in without any properties getting demolished, this would then have left the old A1 for local access saving building the many access roads, it just seems like Wyboston is going to be bisected more than before.
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Re: Black Cat - Cambourne rumour?

Post by KeithW »

thatapanydude wrote: Thu Jun 25, 2020 17:25
As someone who has been through this junction on many a time, I concur its lethal and very nervous turning from the B1040 or further up at Eltisley to the A428 Cambridge bound.

Often I wonder whether its better to just join the "daily" queue from St Neots on A428 just to avoid cutting the corner (just to this horrific mess) as many do from East Beds.

A few finals points would be I would guess the B1040 will now be renembered to take over the section at Eltisley where its currently shared alongside the A428 and I also hope the A421 and A1 gets some tech with MS3 and MS4, both are desperately needed it.
I lived just off the B1040 in Gamlingay and my normal route to Cambridge was to take the back roads to the A1198 at Longstowe and then turn on to the A428 at Caxton Gibbet.
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Re: Black Cat - Cambourne rumour?

Post by KeithW »

NICK 647063 wrote: Thu Jun 25, 2020 17:50 I’ve not read the whole thread so apologies if this question has already been asked but is the plan to number the new road the A421, I remember the A428 getting renumbered from the Bedford bypass to black cat when it used to pass through Great Barford, it would seem pointless doing that if the A421 was to simply flow into the A428 at the new Black cat interchange, having the whole thing numbered A421 surely makes sense.

Also looking at the plans quite a bit of work is to be done through Wyboston, sadly the lovely thatched cottage will be under the A1, it looks like all property access will be via new service roads with the A1 still cutting through Wyboston, surely a western bypass for Wyboston wouldn’t be too hard, looking at satellite view you can fit it in without any properties getting demolished, this would then have left the old A1 for local access saving building the many access roads, it just seems like Wyboston is going to be bisected more than before.
At this stage nothing has been announced as far as I know but I would be surprised if the A428 is not renumbered to be the A421 as that will be a strategic route from Cambridge to the M1, MK and A43 to the M40 and Oxford. Pity about the MK roundabouts though.

The A1 there is the Western Bypass for St Neots. There was a mammoth 1993 proposal to bypass the whole A1 section from Baldock to Alconbury with a new D3(M) motorway to the west but that scheme was cancelled.
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Re: Black Cat - Cambourne rumour?

Post by camflyer »

Good to see that there are only minor changes for the next round of consultation. Enough to show that they have been listening to people but not so many to draw in a lot of new complaints.

As for the Oxford-Cambridge expressway, this will mean than Cambridge to the M1 at J13 is without roundabouts but there is unlikely to be any more development anytime soon as Oxfordshire County Council are against the whole thing and the routing of a MK Southern Bypass through Woburn and Bletchley looks difficult both from an engineering and political perspective.
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Re: Black Cat - Cambourne rumour?

Post by thatapanydude »

camflyer wrote: Thu Jun 25, 2020 19:51 Good to see that there are only minor changes for the next round of consultation. Enough to show that they have been listening to people but not so many to draw in a lot of new complaints.

As for the Oxford-Cambridge expressway, this will mean than Cambridge to the M1 at J13 is without roundabouts but there is unlikely to be any more development anytime soon as Oxfordshire County Council are against the whole thing and the routing of a MK Southern Bypass through Woburn and Bletchley looks difficult both from an engineering and political perspective.
From MK to Oxford, a botch job of widening the A421 to the A43 online is something that I think should be back on the table in lieu of a proper expressway! This can be done in instalments linking the D2 section at Buckingham. I know it’s at-grade etc but still better than nothing!
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Re: Black Cat - Cambourne rumour?

Post by jackal »

Roadiecambs wrote: Thu Jun 25, 2020 17:36
jackal wrote: Thu Jun 25, 2020 17:15
Roadiecambs wrote: Thu Jun 25, 2020 16:54

We'll have to agree to disagree here. I simply don't think that A1SB to A421WB is the only significant movement in this junction, and that all the other movements should be sacrificed as they are not, in some vaguely defined way, "strategic". Indeed the A1SB to A421WB movement is likely to become relatively less important (less strategic?), and the other movements are likely to become relatively more important, given the realignment of the A421/428 to freeflow through the junction, plus all the additional development (referenced upthread) that's happening in the A421/428 corridor that's likely to want to use the A1 NB and SB.

There's been some appalling examples of dumbbell designs causing total gridlock between strategic routes - the M40/A43 being the most obvious, when it was still a single carriageway (as Option A was planned here), so I am highly dubious that it's only stackabouts that generate problems. As I said above, in a fantasy world I would love if this was a free-flowing stack, but in the world we live in of confined budgets, this just ain't going to happen. So the stackabout (to me at least) seems the correct compromise.
Why do you keep strawmaning with this "A1SB to A421WB is the only significant movement" stuff? Obviously the reverse movement and mainlines are significant, as I've repeatedly stated.

M40/A43 is precisely the "use roundabouts for strategic movements" approach that I am criticising and you are endorsing.

If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
OK I am really sorry if you thought my tone was offensive or "strawmanning" here. That certainly was not the intention so I do apologise profusely if that's how it came across.

I am just quite unclear why you think there will be a major traffic issue here. If, as you suggest, all the "non-strategic" turns (A1NB-A428WB etc.) are negligible anyway, then basically either solution (A or C) will work absolutely fine. A will work fine because the "strategic movement" is separated entirely, but the stackabout will also work fine as there will be effectively no conflict on the roundabout. As I said upthread, it's my view that the A1SB to A421WB will become relatively less used, and that the others will become relatively more used, given the development in the corridor. Therefore, I feel it's better to have some decent provision for the other movements (rather than two tight dumbbell roundabouts), even if it's slightly at the cost of the "strategic movement". In both options, A421EB to A1N is freeflow anyway.
No worries, I'm sure you didn't mean anything by it. Honestly not much point in going into it in any more detail, I've said my piece and that ship has sailed in any case.
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Re: Black Cat - Cambourne rumour?

Post by Roadiecambs »

Absolutely, jackal. Even the imperfect scheme is going to be so much better than what we currently have :D
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Re: Black Cat - Cambourne rumour?

Post by KeithW »

thatapanydude wrote: Thu Jun 25, 2020 20:17
From MK to Oxford, a botch job of widening the A421 to the A43 online is something that I think should be back on the table in lieu of a proper expressway! This can be done in instalments linking the D2 section at Buckingham. I know it’s at-grade etc but still better than nothing!
Which is how the A43 was dualled between Juniper Hill and the M40 - small incremental upgrades are much easier to sneak through than high profile big bang projects.
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Re: Black Cat - Cambourne rumour?

Post by Lewis1997 »

KeithW wrote: Thu Jun 25, 2020 17:21
jackal wrote: Thu Jun 25, 2020 17:15 If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
Turns from the A1 onto the A428 take you to Cambridge and its Science Park and via the A14/A11 to Norwich, Ispwich and Felixstowe. If you are heading in that direction from a point north of Welwyn the only alternative is the A505 which is a pretty poor west of Royston. Sounds pretty strategic to me.
Do you mean the A505 being pretty poor east of Royston? I mean the dual carriageway between Royston and Baldock is sub-standard anyway with its poor sight lines and terrible at-grade junctions.
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Re: Black Cat - Cambourne rumour?

Post by jackal »

KeithW wrote: Thu Jun 25, 2020 17:21
jackal wrote: Thu Jun 25, 2020 17:15 If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
Turns from the A1 onto the A428 take you to Cambridge and its Science Park and via the A14/A11 to Norwich, Ispwich and Felixstowe. If you are heading in that direction from a point north of Welwyn the only alternative is the A505 which is a pretty poor west of Royston. Sounds pretty strategic to me.
Having a strategic destination at one end does not a strategic route make - if so any road leading from a village to the national network would be strategic. You need strategic destinations at both ends.

From Stevenage or Letchworth A1+A428 is a vastly longer route than the A505. You might use A1+A428 from Sandy or Biggleswade, though this is not a given as it's again much longer than other roads. In any case, A1/A428 will clearly not be a practical link between major towns/cities/ports so it's not strategic.
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Re: Black Cat - Cambourne rumour?

Post by KeithW »

Lewis1997 wrote: Fri Jun 26, 2020 12:37
KeithW wrote: Thu Jun 25, 2020 17:21
jackal wrote: Thu Jun 25, 2020 17:15 If you don't "get" what a strategic movement is, a simple version is to think about movements between major towns and cities. No major urban centres are linked by turns between the A1 and A428, whereas some are linked by turns between A1N and A421, e.g. MK or Luton to Peterborough. (Strategic movements also take into account other things like port access, but it's a similar story there.)
Turns from the A1 onto the A428 take you to Cambridge and its Science Park and via the A14/A11 to Norwich, Ispwich and Felixstowe. If you are heading in that direction from a point north of Welwyn the only alternative is the A505 which is a pretty poor west of Royston. Sounds pretty strategic to me.
Do you mean the A505 being pretty poor east of Royston? I mean the dual carriageway between Royston and Baldock is sub-standard anyway with its poor sight lines and terrible at-grade junctions.
west - its VERY poor east of Royston, my route from Edgware to Cambridge took me along the A505 to Royston - north on the A1198 to the A603 and east to the M11
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