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Robert Kilcoyne wrote: ↑Sat Mar 09, 2019 16:59
There would surely have to be significant improvements to Junctions 9 and 10 on the M40 if Oxford-Cambridge traffic had to use those junctions; both of those junctions cause frequent delays as it is. I am inclined to think that a more southerly route passing closer to Leighton Buzzard, Aylesbury and Thame may be the best long term solution as it will be virtually impossible to upgrade the A34 at Botley and North Hinksey.
Ideally Junction 9 should be rebuilt as freeflow but doing so without causing gridlock would be quite a trick. As for Junction 10 they spent years tinkering with it. Sounds like we may get Junction 8B next
Here's my rebuild for M40 J9. It's based on the new expressway multiplexing with the A41 via a fork to the NE. The design is called a clovermill (afewexamples).
I've rather cheekily ran two slips over each of the existing bridges. I think this would be entirely possible - they are three lanes plus pavement on both sides, so two single lane slips+narrow hard shoulders+concrete barrier would fit (though ideally you'd widen M40sb->A34 to two lanes). With this design you only need three new bridges.
You could argue that A34->M40sb isn't really necessary, but you might have some **** off locals as it's a long way to the next M40 junction in that direction and the loop isn't hard to provide, so I stuck it in.
roadtester wrote: ↑Sun Mar 10, 2019 02:24
IIRC, the first upgrade was an isolated bit of dualling next to Cambourne that included the current GSJ followed by a gap of some years before the dualling was extended in both directions so that it was continuous between Caxton Gibbet and Girton.
Correct, in the back of my head I the GSJ was developer funded as part of the Cambourne development, although I've no evidence for that. I agree that it's a great piece of road, with separate LAR - I've used it a couple of times, although for me it's a tangental route so doesn't generally help me!
It’s a terrific piece of road and it’s always a massive pain to hit the roundabout at CG going west. I almost always end up in McDonalds in order to fortify myself for the next stretch.
I'm amazed that they were let get away with any of that development, the access is truely appalling - I use the A1198 from Huntingdon to Royston regularly, and the amount of times someone's pulled out in front of me coming out of the development, or sits there blocking the s/b lane because n/b traffic is queued up, practically bringing the whole lot to a halt is simply amazing.
It's pretty much like the planners said "well, there was a pub/restaurant there previously with an access close to the roundabout, so it'll be fine", and the council said "yes, seems reasonable", without thinking that the pub/restaurant was hardly ever used in its later years, and eventually burned down (IIRC), and also traffic has grown enormously on the A428 following the improvements, and the rat running (and signed diversions) via that route to avoid the A14 between Huntingdon and Cambridge, and the development of Cambourne, all of which means that there's constant traffic in and out of the site.
Has anyone noticed the traffic counts on the A421 at Bedford?
Between the A6 and A600 the AADF is at 65k and between the A6 and M1 the AADF is already at 55k. Surely once Caxton to Black Cat is open, these stretches may come under a fair bit of strain.
jackal wrote: ↑Sun Mar 10, 2019 08:14
Here's my rebuild for M40 J9. It's based on the new expressway multiplexing with the A41 via a fork to the NE. The design is called a clovermill (afewexamples).
I've rather cheekily ran two slips over each of the existing bridges. I think this would be entirely possible - they are three lanes plus pavement on both sides, so two single lane slips+narrow hard shoulders+concrete barrier would fit (though ideally you'd widen M40sb->A34 to two lanes). With this design you only need three new bridges.
You could argue that A34->M40sb isn't really necessary, but you might have some **** off locals as it's a long way to the next M40 junction in that direction and the loop isn't hard to provide, so I stuck it in.
I can show you a UK freeflow GSJ that handles large volumes of crossing traffic quite well even at peak and its one I know very well indeed as I use it almost daily. https://www.google.co.uk/maps/@54.56267 ... !1e4?hl=en
Traffic levels are over 100k on the flyover and 80k on the A66
thatapanydude wrote: ↑Sun Mar 10, 2019 13:51
Has anyone noticed the traffic counts on the A421 at Bedford?
Between the A6 and A600 the AADF is at 65k and between the A6 and M1 the AADF is already at 55k. Surely once Caxton to Black Cat is open, these stretches may come under a fair bit of strain.
As an occasional user of the A421 Bedford bypass since it opened in the 1990s the increase in traffic is very obvious. Initially the Bedford bypass was an orphan stretch of high quality D2, but once the Great Barford bypass and then later the Bedford - M1 section has opened it has become much more attractive to through traffic. Rather like the Cambridge to Huntingdon section of the A14, it attracts both east-west and north-south traffic eg. Cambridge - Milton Keynes and A1 (Peterborough) - M1 (Luton and points south). Plus I suspect there's a lot of local traffic junction hopping around Bedford. And then on top of all of that, there's a lot of house building between Bedford and M1 J13. I cycle around this area frequently, and I see much house building going on at Ampthill, Stewartby, Wootton, Wixams and probably elsewhere in the vicinity also. Plus Milton Keynes continues to be boom town, with the area bounded by the M1, A421 and A4146 now being developed. I think even a full D2 expressway standard route from Milton Keynes to Cambridge is going to be congested fairly quickly.
thatapanydude wrote: ↑Sun Mar 10, 2019 13:51
Has anyone noticed the traffic counts on the A421 at Bedford?
Between the A6 and A600 the AADF is at 65k and between the A6 and M1 the AADF is already at 55k. Surely once Caxton to Black Cat is open, these stretches may come under a fair bit of strain.
Perhaps but it runs pretty well. In my experience the main problem is the junctions at each end of the A421. Most of the traffic between the A6 and A600 is there as the A421 is the Bedford Bypass and as usually happens retail parks have sprung up around the intersections with new housing on the north side of the road which has become the defacto southern edge of the Bedford conurbation just as the A14 has become the northern edge of the Cambridge conurbation and has its own share of business and retail parks and associated traffic.
owen b wrote: ↑Sun Mar 10, 2019 14:09
And then on top of all of that, there's a lot of house building between Bedford and M1 J13. I cycle around this area frequently, and I see much house building going on at Ampthill, Stewartby, Wootton, Wixams and probably elsewhere in the vicinity also. Plus Milton Keynes continues to be boom town, with the area bounded by the M1, A421 and A4146 now being developed. I think even a full D2 expressway standard route from Milton Keynes to Cambridge is going to be congested fairly quickly.
There’s also a huge amount of warehousing going up alongside the A421.
The whole arc between Cambridge and Oxford via MK has massive potential and we have to get the full road built in the interests of the national economy,
Also, this is development that takes pressure off London.
roadtester wrote: ↑Sun Mar 10, 2019 14:37
Also, this is development that takes pressure off London.
I'm not sure that's true - development in the East Midlands and North could be taxed and supported appropriately to take pressure off London, I think that the Oxford-Cambridge arc just perpetuates it by increasing growth in and around London...
roadtester wrote: ↑Sun Mar 10, 2019 14:37
Also, this is development that takes pressure off London.
I'm not sure that's true - development in the East Midlands and North could be taxed and supported appropriately to take pressure off London, I think that the Oxford-Cambridge arc just perpetuates it by increasing growth in and around London...
It can take pressure off London precisely because it is near London.
If an investment can’t go to London, or failing that, a place near London, it’s probably going somewhere like Amsterdam rather than the north or the Midlands.
Anyway, the North/the Midlands are getting HS2 and the Northern Powerhouse, and already have had the sort of road investment the outer SE is only just getting now.
thatapanydude wrote: ↑Sun Mar 10, 2019 13:51
Has anyone noticed the traffic counts on the A421 at Bedford?
Between the A6 and A600 the AADF is at 65k and between the A6 and M1 the AADF is already at 55k. Surely once Caxton to Black Cat is open, these stretches may come under a fair bit of strain.
The stage 3 study for the Ox-Cam scheme assumes the entire route between M4 and A14 will be improved to expressway standard. Presumably most of the existing sections will be widened at this time.
thatapanydude wrote: ↑Sun Mar 10, 2019 13:51
Has anyone noticed the traffic counts on the A421 at Bedford?
Between the A6 and A600 the AADF is at 65k and between the A6 and M1 the AADF is already at 55k. Surely once Caxton to Black Cat is open, these stretches may come under a fair bit of strain.
As an occasional user of the A421 Bedford bypass since it opened in the 1990s the increase in traffic is very obvious. Initially the Bedford bypass was an orphan stretch of high quality D2, but once the Great Barford bypass and then later the Bedford - M1 section has opened it has become much more attractive to through traffic. Rather like the Cambridge to Huntingdon section of the A14, it attracts both east-west and north-south traffic eg. Cambridge - Milton Keynes and A1 (Peterborough) - M1 (Luton and points south).
I know colleagues from Peterborough who use it to get to and from Heathrow.
It’s a terrific piece of road and it’s always a massive pain to hit the roundabout at CG going west. I almost always end up in McDonalds in order to fortify myself for the next stretch.
I'm amazed that they were let get away with any of that development, the access is truely appalling - I use the A1198 from Huntingdon to Royston regularly, and the amount of times someone's pulled out in front of me coming out of the development, or sits there blocking the s/b lane because n/b traffic is queued up, practically bringing the whole lot to a halt is simply amazing.
It's pretty much like the planners said "well, there was a pub/restaurant there previously with an access close to the roundabout, so it'll be fine", and the council said "yes, seems reasonable", without thinking that the pub/restaurant was hardly ever used in its later years, and eventually burned down (IIRC), and also traffic has grown enormously on the A428 following the improvements, and the rat running (and signed diversions) via that route to avoid the A14 between Huntingdon and Cambridge, and the development of Cambourne, all of which means that there's constant traffic in and out of the site.
Yes, it’s pretty horrible when it’s busy. The car park fills completely which is particularly bad because the sizing and the spacing of the access and spaces is so tight.
And pulling out onto the A1198 in order to get back to the roundabout can take ages at peak times.
jackal wrote: ↑Sun Mar 10, 2019 16:09..assumes the entire route between M4 and A14 will be improved to expressway standard....
Is that scope creep or a typo?
Neither... the study area includes the A34 to the M4.
Indeed. From p.40:
"All three Expressway options include conversion of sections of the A34, A421, A428 and A1 to Expressway standard to complete the route between the M4 and A14/M11."
On the same page total route length is given as 96-99 miles, depending on routing past Oxford.
A34 (south of Oxford) to M1/A421 is referred to as the 'central section', and is actually only a minority by length (42-46 miles). Of this 16 miles will be online improvements if the route goes west of Oxford (presumably along the A34), and 0 or 6 miles if the route goes east (the 6 miles is from a variant that goes along the M40).
KeithW wrote: ↑Sat Mar 09, 2019 16:30
During the period that these routes were being built the governments in power had a quite different transport policies so long term government plans are unlikely at best and an oxymoron at worst.
It’s not the Govt that has the plan - it’s the CS planners and Depts, and as someone in one, I can guarantee we have our own long term agenda that is entirely “pro us”, the objecive being to guide the Minister down where we want to go, accomodating direction as required.
Interesting on A428 - B.Cat and A1 upgrade Catch 22, I’d always wondered why it stopped at Caxton, especially as the section under the M11 was clearly always DC and therefore the idea of a Westwards DC was reasonably old.
darkcape wrote: ↑Fri Aug 19, 2016 19:35
I thought some of the idea between an Oxford-Cambridge route was to provide a high-quality route that travels on a rough SW-NE alignment that bypasses London and the M25?
There's some good pieces of road in the home counties that can be connected to create some better alternative routes around the capital. The A421 M1-A1, parts of A428 and A120 offer fast routes east-west, but often die into an S2 or at a motorway junction. I've driven Banbury/Milton Keynes a few times and the A421 is rarely above 40mph in rush hour, despite being an NSL road. A route from Oxford to M1 J13 would create better options for people heading SW/NE, giving a faster alternative to the A45, and A43.
Its a good job that this pretty much what it is being planned then is it not ?
The main questions to be resolved seem to be what exact route you take from Brogborough to Oxford.
marconaf wrote: ↑Sat Mar 16, 2019 23:09
Interesting on A428 - B.Cat and A1 upgrade Catch 22, I’d always wondered why it stopped at Caxton.
A fair chunk of traffic leaves the A428 to head up to Papworth, AADF tails off after this point towards St Neots.
The fact that between Papworth and St Neots the road is a slow congested S2 with lots of flat junctions has rather a lot to do with that. The A428 upgrade was justified on the basis of increased commuter traffic and the building of the new town at Cambourne which is why it stops at Caxton. There was also the Catch 22 mess associated with an A1 upgrade for which there had been no funding. The A428 upgrade like the Black Cat replacement has been on hold since 1994.
