A428 Black Cat - Caxton Gibbet improvement

[Median]

I've read this whole thread and so far no-one has mentioned a major problem with the "Felixstowe to the M1" A14-A428-A421 pipe dream.

Under the A14 Cambridge to Huntingdon upgrade scheme that was given the go-ahead yesterday, the A428 will be permanently reduced to one lane each way at Girton. They are pinching a couple of lanes from the A428 to give to the A14. Even if today's A428 could form part of a major trunk route, it certainly won't be able to after the A14 upgrade. I predict that the Black Cat to Caxton dualling, if it happens, will immediately break the Girton interchange. Sorry to be a doom-monger!

[Truvelo]

I suspect Girton will be built to allow D2 for the A428 with the planned D1 being accomplished by hatching. It would be foolish not to allow an additional lane to be added when the A428/A421 is eventually upgraded.

[roadtester]

The local MP (Daniel Zeichner, Labour) was grumbling in the Cambridge News today about them stinting on Girton as well but I got the feeling that like most other locals, he's just relieved the project is getting under way at last and he was inclined going out of his way to conduct an over-zealous oral examination of a welcome equine present.

[Median]

I suspect Girton will be built to allow D2 for the A428 with the planned D1 being accomplished by hatching. It would be foolish not to allow an additional lane to be added when the A428/A421 is eventually upgraded.

It turns out that you are mostly correct. I was unwittingly using an outdated plan of the scheme from April 2014 (https://www.gov.uk/government/consultat ... sed-scheme) and hadn't realised that the plans submitted in Jan 2015 (http://infrastructure.planninginspector ... nt-scheme/) were different.

The April 2014 plan really did restrict the A428 quite badly but the Jan 2015 plan is better. Westbound, the A428 now gets 2 lanes all the way through Girton, so that's sorted. Eastbound, the A428 is painted down to 1 lane as it goes under the (yet to be built) A14W right-turn flyover although the underpass appears to be about 3 lanes wide. After that, though, there's no room for the A428 to open up to 2 lanes before it joins the slip road from the M11N. They would have to add another lane to the north side of the M11N slip road loop to allow the A428 to continue as 2 lanes. I think that could be done without rebuilding the existing bridges, so not too bad.

[Median]

The local MP (Daniel Zeichner, Labour) was grumbling in the Cambridge News today about them stinting on Girton as well but I got the feeling that like most other locals, he's just relieved the project is getting under way at last and he was inclined going out of his way to conduct an over-zealous oral examination of a welcome equine present.

Yes, I read that and I agree with you. However, the plan that Zeichner supported was not about safeguarding the capacity of the A428-Felixstowe route - it was more about helping local traffic zip through the junction in various directions.

[jackal]

I suspect Girton will be built to allow D2 for the A428 with the planned D1 being accomplished by hatching. It would be foolish not to allow an additional lane to be added when the A428/A421 is eventually upgraded.

It turns out that you are mostly correct. I was unwittingly using an outdated plan of the scheme from April 2014 (https://www.gov.uk/government/consultat ... sed-scheme) and hadn't realised that the plans submitted in Jan 2015 (http://infrastructure.planninginspector ... nt-scheme/) were different.

The April 2014 plan really did restrict the A428 quite badly but the Jan 2015 plan is better. Westbound, the A428 now gets 2 lanes all the way through Girton, so that's sorted. Eastbound, the A428 is painted down to 1 lane as it goes under the (yet to be built) A14W right-turn flyover although the underpass appears to be about 3 lanes wide. After that, though, there's no room for the A428 to open up to 2 lanes before it joins the slip road from the M11N. They would have to add another lane to the north side of the M11N slip road loop to allow the A428 to continue as 2 lanes. I think that could be done without rebuilding the existing bridges, so not too bad.

I wouldn't really call that the A428 getting two lanes westbound - lane one is for the A428 but lanes two and three are for the A14 (it is possible to turn from lane two to the A428, which is I guess what you mean). The A428 capacity through the junction is a lot less than two lanes in both directions. However, it is obviously built for two or more lanes throughout, as indeed pretty much every modern A road carriageway is. The limiting factor is the A14 Cambridge northern bypass, which would need to be D4 or wider to accommodate two lanes for the A14 and two for the A428. I expect this widening would happen were the full A34-A14 route completed.

[jackal]

An 'A428 Black Cat to Caxton Gibbet' link has popped up at http://www.highways.gov.uk/roads, but the link seems to be dead.

A quick Google turns up this FOI response from March, including the following:

A428 Black Cat to Caxton Gibbet
 Details of any proposed routes and what stage the proposals are at
At present, we are identifying options, which we estimate will take another 12 months.
This will lead to route selection and appraisal in due course.
 What consultations have taken place or planned
No consultations have taken place and are yet to be planned. As we make further
progress, we will liaise with regional and local stakeholders as well as residents to allow
for consultation and feedback.
 Plans of route options currently available
There are no route options currently available.

If route selection and appraisal will only start in March it seems unlikely that construction could really begin by Spring 2020.

[Truvelo]

Plans of route options currently available
There are no route options currently available.

Give me half hour and I could knock up something that would blow the socks off anything designed in Texas

[Median]

An 'A428 Black Cat to Caxton Gibbet' link has popped up at http://www.highways.gov.uk/roads, but the link seems to be dead...

The link now goes here: http://www.highways.gov.uk/roads/road-p ... ton-Gibbet.

The route options are still to be identified, but at least there's a timetable and a 'subscribe to be alerted' link.

[timetex]

I've joined the forum today to ask a question about the proposed Black Cat to Caxton Gibbet 'upgrade'... so I'm hoping someone can shed some light on it!

I know that route proposals are still being considered, but a quick Google search earlier threw up a 'map' on a local newspaper article:

http://www.huntspost.co.uk/news/long_te ... _1_3564400

Which, in April 2014, predicts or indicates a very specific route for the upgraded road.

Setting aside the Black Cat questions around the potential junction types, integration with the existing / proposed A1 routes, etc. - what are people's general views about 2 things:

1) the junction at Caxton Gibbet - which this map indicates joining to the north of the existing A428 - any ideas why?

2) along the route - the map shows the new road crossing the A428, then running VERY close to it for a distance (near Croxton / Eltisley) before diverging again.

Any ideas why the route would go to the north of the existing A428 and not simply pick a cross country route diagonally from Black Cat to the south western point of the Caxton Gibbet roundabout, as this seems eminently more direct than looping north of the existing A428.

Basically I want to try and understand if this map has ANY basis in 'fact' or is purely a random line drawn on a map by a journalist or politician. I thought the best place to ask this was a in forum of people who seem to know a LOT about the technical and practical side of road building, so I'm hoping for some useful answers!

[c2R]

I think the map is part fantasy but possibility. I think that the general route outline may be provided as an option, but there would need to be more detailed drawings - the article itself also talks about online dualling of the route.

Any part of the route to the north of Caxton Gibbet would probably be around fitting the road in with a new grade separated junction - probably a dumbell arrangement with the existing roundabout used as a southern one in the pair.

[owen b]

Any ideas why the route would go to the north of the existing A428 and not simply pick a cross country route diagonally from Black Cat to the south western point of the Caxton Gibbet roundabout, as this seems eminently more direct than looping north of the existing A428.

I don't know, but here's three speculative possible reasons :
i) a "direct" cross country route wouldn't be much shorter by the time you've curved between (or around) Abbotsley village and Abbotsley hotel, and then again south of Croxton Park and Eltisley.
ii) less damaging (noise, environment etc.) to put the new road in the same corridor as the existing road where reasonably practicable.
iii) a northerly route enables an intermediate junction with the old road west of Croxton which local traffic for St.Neots can use, rather than having to continue all the way along the old road to Caxton Gibbet. So you get more relief for the old road from Croxton to Caxton Gibbet.

[KeithW]

I've joined the forum today to ask a question about the proposed Black Cat to Caxton Gibbet 'upgrade'... so I'm hoping someone can shed some light on it!

I know that route proposals are still being considered, but a quick Google search earlier threw up a 'map' on a local newspaper article:

http://www.huntspost.co.uk/news/long_te ... _1_3564400

Which, in April 2014, predicts or indicates a very specific route for the upgraded road.

Setting aside the Black Cat questions around the potential junction types, integration with the existing / proposed A1 routes, etc. - what are people's general views about 2 things:

1) the junction at Caxton Gibbet - which this map indicates joining to the north of the existing A428 - any ideas why?

2) along the route - the map shows the new road crossing the A428, then running VERY close to it for a distance (near Croxton / Eltisley) before diverging again.

Any ideas why the route would go to the north of the existing A428 and not simply pick a cross country route diagonally from Black Cat to the south western point of the Caxton Gibbet roundabout, as this seems eminently more direct than looping north of the existing A428.

Basically I want to try and understand if this map has ANY basis in 'fact' or is purely a random line drawn on a map by a journalist or politician. I thought the best place to ask this was a in forum of people who seem to know a LOT about the technical and practical side of road building, so I'm hoping for some useful answers!

Well the direct route is quite impractical as the terrain to the south of the A428 is dominated by the greensand ridge while to the north you are on the Great Ouse flood plain and would have to contend with deep lakes and marshland (which are also nature reserves). The most practical and cheapest route is to take the A421 across the Great Ouse south of Little Barford then head NE to pass just west of the historic moated site of Wintringham Hall.

Routing the new road south of the A428 would involve crossing Croxton Park, felling some prime woodland, impinging on grade 1 listed buildings and then demolishing a lot of very expensive housing in Croxton and Eltisley. I can think of no route that would raise more opposition. On the other while going north simply takes you over agricultural land and allows an easy approach to the A428 at Caxton Gibbet. The Hunts Post map makes perfect sense if you know the area.

The OS map view on Bing Maps shows it quite well.

[timetex]

I've joined the forum today to ask a question about the proposed Black Cat to Caxton Gibbet 'upgrade'... so I'm hoping someone can shed some light on it!

I know that route proposals are still being considered, but a quick Google search earlier threw up a 'map' on a local newspaper article:

http://www.huntspost.co.uk/news/long_te ... _1_3564400

Which, in April 2014, predicts or indicates a very specific route for the upgraded road.

Setting aside the Black Cat questions around the potential junction types, integration with the existing / proposed A1 routes, etc. - what are people's general views about 2 things:

1) the junction at Caxton Gibbet - which this map indicates joining to the north of the existing A428 - any ideas why?

2) along the route - the map shows the new road crossing the A428, then running VERY close to it for a distance (near Croxton / Eltisley) before diverging again.

Any ideas why the route would go to the north of the existing A428 and not simply pick a cross country route diagonally from Black Cat to the south western point of the Caxton Gibbet roundabout, as this seems eminently more direct than looping north of the existing A428.

Basically I want to try and understand if this map has ANY basis in 'fact' or is purely a random line drawn on a map by a journalist or politician. I thought the best place to ask this was a in forum of people who seem to know a LOT about the technical and practical side of road building, so I'm hoping for some useful answers!

Well the direct route is quite impractical as the terrain to the south of the A428 is dominated by the greensand ridge while to the north you are on the Great Ouse flood plain and would have to contend with deep lakes and marshland (which are also nature reserves). The most practical and cheapest route is to take the A421 across the Great Ouse south of Little Barford then head NE to pass just west of the historic moated site of Wintringham Hall.

Routing the new road south of the A428 would involve crossing Croxton Park, felling some prime woodland, impinging on grade 1 listed buildings and then demolishing a lot of very expensive housing in Croxton and Eltisley. I can think of no route that would raise more opposition. On the other while going north simply takes you over agricultural land and allows an easy approach to the A428 at Caxton Gibbet. The Hunts Post map makes perfect sense if you know the area.

The OS map view on Bing Maps shows it quite well.

Thanks for the replies so far.

There is also a Grade 2 Listed building just north of the A428 (North Farm) and housing along part of that stretch.

Just how far should / would the route have to be away from these, and would you be worried if you owned North Farm (PE19 6SR) or other property along the A428?

[KeithW]

Thanks for the replies so far.

There is also a Grade 2 Listed building just north of the A428 (North Farm) and housing along part of that stretch.

Just how far should / would the route have to be away from these, and would you be worried if you owned North Farm (PE19 6SR) or other property along the A428?

Obviously you would be concerned and you would certainly want 2 main guarantees
1) Adequate compensation for the land lost
2) Satisfactory access to the remaining land

I would expect this to be handled in much the same way as the section east of Caxton Gibbet. That is to say retain the old road for local access and build a flyover for that local traffic as was done at Bourn

[jackal]

As reported by wrinkly, there is a consultation to start on Monday, with three route options (link). There are also 'three options for improving the Black Cat roundabout':

Option A – removal of the existing roundabout, construction of two roundabouts to the west of the current roundabout, slip roads for drivers to get from the A421 to the A1, and from the A1 to the A421. The A1 would become a free-flow continuous road going under the slip roads.

Option B – keeping the existing Black Cat roundabout and adding a new free-flow continuous link from the A421 eastbound towards the A1 northbound. The A1 would remain the same but the addition of slip roads would provide a free-flow link bypassing the roundabout for traffic moving southbound onto the A421.

Option C – enlarging the existing Black Cat roundabout, the A1 would become a continuous free-flow road under the widened Black Cat roundabout and slip roads would be built between the A421 and the A1.

This is all quite ambiguous - in particular, it doesn't expressly say that the A421/A428 will have its own grade separated mainline. Assuming that it does, option 1 would be similar to a stackabout but with two roundabouts offset to the side rather than one in the middle, option 2 would be a roundabout interchange but with extra freeflow (like this), option 3 would be a stackabout. We'll know on Monday, anyway.

[wrinkly]

As reported by wrinkly, there is a consultation to start on Monday,

I had a feeling there was another thread I should have said it in but couldn't remember what it was.

[jackal]

Consultation now open: https://highwaysengland.citizenspace.co ... on-gibbet/

The junction options are as per my post above, with one key difference - as well as grade separating both mainlines, Option A has freeflow for A1sb->A421wb. I'm impressed.

As for the routes, all are offline, but one stays quite close to the A428, and has GSJs at Black Cat, Cambridge Road and Caxton Gibbet. The other two cut across open terrain either side of Abbotsley, and only have GSJs at Black Cat and Caxton Gibbet. They are all in the 11.4-11.7 mile range.

[Bryn666]

In terms of 'neatness' it's Purple route and option C for me.

I think the construction of option A will be its undoing; it's quite intensive structures wise and looks like quite a lot of disruption to build.

Option B is ugly as sin.

One pity is that the kink around the marina will still remain - the opportunity to smooth out that section down to Tempsford should be taken.

[timetex]

We decided to pull out of the house purchase, but have still retained an interest in what happens here.

The orange route practically goes through the back garden of the property we were purchasing, so would have been an utter nightmare / total blight. The other 2 routes are nowhere near.

Definitely some good options for the Black Cat, too...