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jackal wrote:I think someone on here actually commented during the A421 consultation that it should be future proofed in that way and, low and behold, it was.
No future proofing made other than currently closed off lanes for projected growth along the A421 to MK and to allow the future dual carriageway A421 to MK to plug in nicely. Given the Oxford-Cmbridge route corridor is currently a study/consultation, at the time there was no route for the A421/M1J13 scheme to future proof...
The junction as built can far more easily accommodate an extension of the A421 mainline than the original four roundabout design could. I'd call that future proofing given the designers were certainly aware of the idea of a grade separated MK bypass.
Well there may be a happy geometrical accident that looks convincing but there was no account taken of any road or flow making a fourth arm at the roundabout at the end of the A421. Obviously the design team weren't aware of the expressway proposal that hadn't been made at the time - the only proposal on the table at the time was the dualling of the A421 into MK and traffic flows associated with that dualling were taken into account.
jackal wrote:In that connection, I managed to find A303Paul's post from a decade ago that I was talking about. It's quite interesting!
A303Paul wrote:Well its not quite This but I think my alternative proposal (I am the mysterious resident of Flitwick) definitely influenced the final proposal.
I am particularly pleased that the draft orders layout will allow for full grade separation of the A421 as and when the MK southern bypass is built.
A little disappointed that the freeflow from M1 to A421 Bedford was not included but it is a big improvement on the previous proposals. Particularly for Northbound traffic from the M1 to the A421 which originally had three roundabouts but now only has to pass two with a choice of only two directions.
Would rather have seen a roundabout under the new GSJ with the M1 slip diverted to it. This would have allowed a freeflow A421 W to M1 S lane however the layout does allow for virtually the the full adpotion of my proposal in the future. [SMUG](self congratulates )[/SMUG]
I met Paul at one of the public consultations and explained the rationale behind the junction and how removing the through traffic (IIRC at the time some 50% of the traffic crossing the M1 J13 bridge was Bedford - MK and vice versa) from M1 J13 would allow the motorway junction to work better, hence eliminate the need for major remodelling and rebuilding the J13 bridge itself and plug into any M1 widening scheme better . The grade separation at Salford Road was a straightforward saving on journey time for the MK - Bedford journeys against the at-grade roundabout and was a "no-brainer".
M5Lenzar wrote:A road like this should be at least a D3M Motorway. Why do we listen to the so-called environmentalists who are simply standing in the way of progress?
Well, in simple terms we follow a due process that is laid down in an Act of Parliament that allows for orders to be proposed, examined in public and confirmed or refused according to considered decision of the examining authority. There are many competing interests and conflicting Acts of Parliament that have to be taken into account and a decision is made that takes into account all representations made by all parties, statutory consultees, regulators and interests.
Just because, say, more than half the people in a room at a given time think that it would be a good idea to build that route as a motorway does not mean that that quasi-democratic decision can subvert the due process laid down by Parliament. Where would we be if that happened and we decided planning policy in that way?
fras wrote:Surely if a new route is to be built it should be motorway.
Do we really want these new roads to cater for all traffic, because that is the implication ? Cyclists can use the old road, (less busy with the new road), and surely we don't want pedestrians, tractors, traction engines going to/from rallies, farmers herding cattle, pensioners on pensioner trolleys, geese going to market etc etc, on these new roads ?
M41? Could eventually be extended to meet the M4 at jct 15 outside Swindon. Would complement a northern and eastern bypass of the M25 via a Lower Thames Crossing which could be numbered M10 and an upgrade to the A34 - perhaps to M34?. The M34 would provide a western bypass of the M25. I realise I've resurrected two ex motorway numbers with the M10 and M41. I've also added to the proposed route map the A120(M) upgrade as a spur from the M10 at Great Dunmow to the A12 at Marks Tey; the extended A13 from the A127/A1245 jct to Maplin Sands International Airport; the extended M11 to the A1(M) at Alconbury; and the A14 between the A1 and M1 upgraded to M14.
I've added the A41 Aylesbury dual carriageway southern bypass and A41 off-line dual carriageway link to M40 jct 10. I've also added the M12 from M25 jct 28 to A12 jct 20b which is an on-line upgrade with improvements to the sharp bends of the Ingatestone bypass (the current A12 route is off-line to the original highway between these jcts and therefore there would already be an alternative route for non-motorway traffic). The M10 also multiplexes with the M12 between M12 (obviously currently A12) jcts 17 and 19. The M12 would not need to be built between the M25 and M11 jct 4 as the M25/M11 route can be used to reach central London or indeed the M25/A13 route. Obviously signs should direct traffic via the M25/M11 or M25/A13 to discourage anyone without local knowledge from using the very slow A12 Colchester Road and Eastern Avenue route.
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Last edited by Philip_Baum on Mon Nov 28, 2016 20:43, edited 5 times in total.
Supposing the expressway was plugged in as a continuation of the A421 mainline at M1 J13, what would be the major turning movements? My initial thought is that M1N<->expressway and M1S<->Bedford would probably be the most important in strategic terms, though MK<->Bedford is reportedly heavy too.
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. With this design you only need three new bridges (plus pedestrian facilities).
You could argue that A34<->M40S isn't really necessary, but you'd 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.
When I was a lad, I temporarily worked for BCC in the 'forward planning' department. One of my jobs was taking levels for the proposed Newport Pagnell bypass. Lines were drawn on the map showing a northwards projection to include Sherringham and Olney. Every time a local councillor got wind of the proposals, the next village along the A509 wanted a bypass as well! Cost obviously stopped it at Sherringham.
I think it has been mentioned before, but a proposal was made for a bypass of Wing on the A418. The published plan for consultation showed a dual 3 lane bypass, which seemed a bit OTT. Another plan I've seen for a southern bypass of Aylesbury, shows a similar grand scheme passing between Stoke Mandeville and Aylesbury, just where the old transport café was. Both these schemes were seen as an Oxford -Cambridge motorway by stealth.
A41 southern bypass of Aylesbury with off-line link to M40 jct 10 that crosses the Oxbridge expressway. Also I think the Oxbridge Expressway could be numbered A420 as an extension of the existing A420 from Oxford (of course multiplexing with the A34).
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Last edited by Philip_Baum on Mon Nov 28, 2016 21:07, edited 1 time in total.
The A41 could potentially be upgraded to motorway in stages with each motorway section numbered A41(M) like the Tring bypass was. Eventually if the entire route is upgraded to motorway it could be renumbered M41 so on second thoughts I think this number should be reserved for the Watford to Ardley Motorway rather than the potential Oxbridge Motorway. It's difficult finding a suitable number because the A43 could also one day be upgraded to M43. Maybe M44 then as I don't think the A44 will ever need to be upgraded? Or maybe a 3 digit motorway number?
Even though the English motorway numbering system seems simple and logical with the single digit routes based on London as a motorway hub with the routes being numbered clockwise from the M1, with these marking the zone boundaries for the two digit routes (with the exception of the M2 where the River Thames makes more sense as the zone boundary). It can get quite messy numbering the two digit routes if you start numbering the single digit routes differently to the associated highway (e.g M5 and A38). The English motorway numbering system does not always use the number of the highway or highways it replaces for motor traffic like in Scotland. I guess there are pros and cons for both numbering systems. If the Scottish system were used then, for example, the M1, M6 and M54 route would be numbered M5; the M1 between the M6 and A50 would be numbered M50, the M1 between the A50 and M18 would be numbered M60 and the M1 between the M18 and Leeds would be numbered M61. Following this system, if all the A1(M) sections ever became linked by motorway it would be numbered M1. The problem with the Scottish system on the other hand is that; what would sometimes be better as a single motorway route number such as, for example, the M1 and M25 would become several motorway numbers.
However, the Scottish numbering system has been used in England for a number of motorways or sections of them. The M11 between London and A11, the M18 between the A1(M) and M180, M2, M20, M23, M25 between the M26 and A3, M4 between London and the M5, M40 between London and Oxford, M56, M58 (sort of), M6 north of the M61 and M62 between Manchester and Leeds use the number of the associated highway. I know that some of these motorways were built in sections e.g. the A4(M) with the A4(M) sections becoming M4 when linked to form a continuous motorway route. I think I prefer the Scottish numbering system with exceptions made where it would become non-sense e.g. in the case of the M25. It obviously makes more sense in the case of the London Orbital that it has one number even though the western, northern and eastern sections do not replace the A25. The problem with the English system comes to light when considering, for example, the A1(M) as, if the A1(M) motorway sections are linked to form a continuous motorway route between London and Newcastle it would not be able to be renumbered as M1, with the exception of the section between Leeds and Newcastle, given this number is obviously already in use between London and Leeds. The same is the case for the A3(M) as the M3 is already used for the motorway between London and Southampton. Under the Scottish system the current M3 would be M30 from London to jct 8 and M33 from jct 8 to Southampton. Perhaps, like the temporary AX(M) number, the M30 should be the temporary number between London and Southampton until a motorway is built (if ever) west of jct 8. Then the new motorway should take the M30 number (yes I know - it could also be M303 but two digits is better and it also follows the A30 although further north) and the section between jct 8 and Southampton should then be renumbered M33.
Last edited by Philip_Baum on Mon Nov 28, 2016 22:42, edited 6 times in total.
Designing a good design for M1J13 after upgrading is tricky. Here's my attempt; I tried to make as many movements as possible freeflow.
Note: That M1SE - A421NE turn is pretty tight, not sure if it fits or not. If not, it doesn't matter because there's another freeflow way to do this movement on the map.
6637 wrote:Designing a good design for M1J13 after upgrading is tricky. Here's my attempt; I tried to make as many movements as possible freeflow.
A421.png
Note: That M1SE - A421NE turn is pretty tight, not sure if it fits or not. If not, it doesn't matter because there's another freeflow way to do this movement on the map.
I agree, it's a tough one! This is my best attempt at it. Looks ugly but does freeflow all the Oxbridge expressway<->M1 movements, plus MK<->Bedford (which currently accounts for 40% or so of turning movements here).
Thanks for that. From a quick skim the main takeaways for me were:
- There are seven costed options (one based on route A, three based on B, three based on C)
- There's also a map (p. 39) showing an additional route merging with the A34 near Didcot, as speculated above, though this doesn't seem to have any costings.
- The option costs range from £3bn-£3.5bn.
- 'All three [sic] 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'.
- The A (Aylesbury) and B (EWR) options are overwhelmingly new build, while the C options (A421) are more of a mixture of new and widened/improved (see table on page 40 for full details).
- The real kicker: expected opening date, 2031!!! So either they're pushing it back to RS3 (i.e. construction to start 2025-30) or they plan to take 6+ years for construction alone.
Philip_Baum wrote:A41 southern bypass of Aylesbury with off-line link to M40 jct 10 that crosses the Oxbridge expressway. Also I think the Oxbridge Expressway could be numbered A420 as an extension of the existing A420 from Oxford (of course multiplexing with the A34).
The A41 southern bypass passes close to Cubington useful for the 4 runway airport to replace Heathrow.
kit wrote:Not linking it with the A34 would be a massive mistake, bearing in mind how much strategic traffic uses the route.
It's also disappointing that there are no more detailed maps, how can they make any accurate estimates or plans from a "tube line" style map?
All of the options assume a connection to the A34, and A34 improvements as well.
I'm sure they have more detailed maps, they just don't want to unnecessarily blight seven or eight different routes at such an early stage.
It's weird that they don't even mention the standard of the expressway, though. The maps and description show the recently completed A421 expressway being upgraded, which makes me wonder if maybe the whole thing will be D3 or better. If so, they better tell the Black Cat-Caxton Gibbet team!
jackal wrote:All of the options assume a connection to the A34, and A34 improvements as well.
I'm sure they have more detailed maps, they just don't want to unnecessarily blight seven or eight different routes at such an early stage.
It's weird that they don't even mention the standard of the expressway, though. The maps and description show the recently completed A421 expressway being upgraded, which makes me wonder if maybe the whole thing will be D3 or better. If so, they better tell the Black Cat-Caxton Gibbet team!
I thought the A34 improvements mentioned were the vague ones to pop a couple of VMSes here and there, if they can find any at the back of the cupboard? No actual capacity improvements.
If we were a more progressive country we'd publish a route between two centres of academic excellence to encourage high quality investment and jobs along the route, not because it might marginally reduce a couple of house prices (and improve many more homes suddenly within commuting distance of Cambridge, Oxford and MK).
I didn't want to believe my Dad was stealing from his job as a road worker. But when I got home, all the signs were there.
jackal wrote:All of the options assume a connection to the A34, and A34 improvements as well.
I'm sure they have more detailed maps, they just don't want to unnecessarily blight seven or eight different routes at such an early stage.
It's weird that they don't even mention the standard of the expressway, though. The maps and description show the recently completed A421 expressway being upgraded, which makes me wonder if maybe the whole thing will be D3 or better. If so, they better tell the Black Cat-Caxton Gibbet team!
I thought the A34 improvements mentioned were the vague ones to pop a couple of VMSes here and there, if they can find any at the back of the cupboard? No actual capacity improvements.
There is a 'A34 technology enhancements' scheme due to start in 2019/20. But we can be pretty certain the longer term plan is to widen or bypass at least some of the A34 north of the M4. It's true that the current report is not specific about that, but that's hardly surprising given it doesn't even mention the standard of the expressway.
6637 wrote:Designing a good design for M1J13 after upgrading is tricky. Here's my attempt; I tried to make as many movements as possible freeflow.
A421.png
Note: That M1SE - A421NE turn is pretty tight, not sure if it fits or not. If not, it doesn't matter because there's another freeflow way to do this movement on the map.
I agree, it's a tough one! This is my best attempt at it. Looks ugly but does freeflow all the Oxbridge expressway<->M1 movements, plus MK<->Bedford (which currently accounts for 40% or so of turning movements here).M1 J13 large.png
Hmm, I don't think that's very a good design due to the tightness of the loops. Probably better to use more land for the junction and thus have more gradual curves, like on my map.
Note: I've just noticed that on my map, the new-expressway-northeastbound-to-M1-southeastbound movement isn't freeflow. I should modify the map a bit, adding a freeflow link.
