A57/A628 Mottram Tintwistle bypass

[the cheesecake man]

I always assumed most traffic using the woodhead/snake corridors would use the southern half of the M60 and anyone going north would go up to the M62.

Not at all. Heading south towards Cheshire there's sensible alternatives such as A6 and A555.

Heading north it's quite a detour to Huddersfield or Lofthouse for the M62.

[Peter Freeman]

Personally I'd rather trial the DDI at J7 instead where the A56 crosses over because this has huge active travel potential for a corridor that desperately needs it. I even did a video on my YT channel about that one: https://www.youtube.com/watch?v=dFlMjATjNG4

Conversion of a standard diamond to DDI: dead easy. And I can't see any site difficulty there. It would certainly be the best action there, but is there any intention for any action?

[jackal]

While I like SPUIs Denton Island is an inappropriate site for one, especially if we're assuming A628 improvements to make this a truly strategic route. While better than a roundabout an SPUI is not a system interchange and would only be a stopgap, and a very expensive and disruptive one at that.

It's more practical and certainly more effective to take the main right turns off the island completely with the trumpet. Golf courses are not sacrasanct and have land taken off them when required (IIRC they're actually closing the Arundel one to make way for the bypass).

J7 is indeed a better SPUI site.

[Bryn666]

While I like SPUIs Denton Island is an inappropriate site for one, especially if we're assuming A628 improvements to make this a truly strategic route. While better than a roundabout an SPUI is not a system interchange and would only be a stopgap, and a very expensive and disruptive one at that.

It's more practical and certainly more effective to take the main right turns off the island completely with the trumpet. Golf courses are not sacrasanct and have land taken off them when required (IIRC they're actually closing the Arundel one to make way for the bypass).

J7 is indeed a better SPUI site.

The A628 is never going to be vastly improved beyond what's there now despite TfN's dreaming of a mega tunnel, the best you're going to get is limited safety improvements at the A6024 and highly likely the rest will be reduced speed limits and enforcement measures because the National Park is an insurmountable obstacle. In this context a SPUI at the end of the M67 is a vast improvement on what's there now and would complement the limited bypass works at Mottram whilst providing a more reliable interchange for the traffic already using it without inviting shedloads more onto it. It's only a stopgap if you believe in a never ending increase of driving, which is contrary to transport policy - or it should be if you still want a planet to bother with.

The trumpet also means you're stuck with a substandard roundabout underneath because you can't fit in a signal junction under the flyover you'd need to build across it and this means being stuck with poor active travel facilities meaning the complex remains a barrier to anyone not driving. We've demonstrated the SPUI can be built within the existing structures so disruption is not that excessive during conversion. The bulk cost is the new structure, but it's still going to cost less than 500+ metres of new trumpet flyovers.

Incidentally, at J7 a SPUI is impossible to build due to the layout of the structure carrying the M60 and it's a needless change ripping out a <20 year old bridge to provide an overblown design when a DDI would do the same job just as well.

I'd rather structural megabucks were spent on lessening the severity of the clockwise bend at M60 J25 to get rid of the blind curve which even a 50 limit and SPECS does little to mitigate. NH are desperate to get rid of the right hand lane gain because "non-standard" yet seem perfectly content to keep that bend. Just shows how skewed their priorities are in terms of safe systems design.

[Peter Freeman]

Incidentally, at J7 a SPUI is impossible to build due to the layout of the structure carrying the M60 and it's a needless change ripping out a <20 year old bridge to provide an overblown design when a DDI would do the same job just as well.

You took the words out of my mouth - I was just about to reply to Jackal saying the same thing. A DDI is dead easy there, but a SPUI is impossible. J24: either, but SPUI best.

[Peter Freeman]

While I like SPUIs Denton Island is an inappropriate site for one, especially if we're assuming A628 improvements to make this a truly strategic route. While better than a roundabout an SPUI is not a system interchange and would only be a stopgap

A SPUI is not normally a system interchange, but it can supply at least 1.5 lanes-worth of traffic to each of M60nb and M60sb, which is as much as M60 can take in addition to its current load.

(I used M67wb 60K AADT AM-peak unidirectional. Is that correct? It sounds too high.)

, and a very expensive and disruptive one at that.

Not very disruptive. Cost about the same as M6J19 - that was an almost similar scale of work (for little gain, and mis-spent, IMHO).

I support the Mottram scheme, and I think it's the correct scheme, for now. It's pragmatic, affordable, incremental, and sufficient for Glossop, Snake and Woodhead-current traffic. I'd next support extending past Hollingworth and Tintwistle. Only after that, the A628 etc over the hills to Sheffield should incrementally receive capacity and safety upgrades, but not motorway standard. It could consist of limited lengths of DC, generous climbing lanes (S2+1) on most up-gradients, but still S2 where the engineering challenges are too expensive. The reason I think this way is that unless the UK's economic position radically improves, there will be no funding for major all-in-one-go schemes (LTC and Stonehenge your final two?), and especially not a Pennines Tunnel. Unlike where I live, the UK does not have a burgeoning population, your infrastructure is mature, and small-scale high-value incremental is the way to go.

To return to Denton - it will not, from Woodhead, Snake and Glossop, gather more traffic than the SPUI and the M60 can take (unless you're going to double-deck M60 ...?).

It's more practical and certainly more effective to take the main right turns off the island completely with the trumpet. Golf courses are not sacrasanct and have land taken off them when required (IIRC they're actually closing the Arundel one to make way for the bypass).

I agree, the trumpet suggestion is good, but I don't think NH or Manchester can afford that either. The M60 has lots of bottlenecks to fix, unless we all join Bryn on his bike.

[jackal]

I had time overlap with one of Peter's posts and hastily added the J7 bit when I saw it, assuming we were still talking SPUIs. Of course a DDI is better given it's a two span bridge. My bad.

The A628 is never going to be vastly improved beyond what's there now despite TfN's dreaming of a mega tunnel, the best you're going to get is limited safety improvements at the A6024 and highly likely the rest will be reduced speed limits and enforcement measures because the National Park is an insurmountable obstacle. In this context a SPUI at the end of the M67 is a vast improvement on what's there now and would complement the limited bypass works at Mottram whilst providing a more reliable interchange for the traffic already using it without inviting shedloads more onto it. It's only a stopgap if you believe in a never ending increase of driving, which is contrary to transport policy - or it should be if you still want a planet to bother with.

Vastly maybe not, but further A628 improvements are pretty inevitable I'd have thought. For starters the residents of Hollingworth and Tintwistle are not going to be too happy with the extra traffic resulting from their neighbour's bottleneck getting bypassed and will want the same.

As for Denton, I don't see how one can in the same breath say that increasing traffic is ending the world and that we should build an SPUI that will increase traffic. A funky junction design doesn't give you a discount on the radiative forcing effect of CO2 emissions.

[Bryn666]

I had time overlap with one of Peter's posts and hastily added the J7 bit when I saw it, assuming we were still talking SPUIs. Of course a DDI is better given it's a two span bridge. My bad.

The A628 is never going to be vastly improved beyond what's there now despite TfN's dreaming of a mega tunnel, the best you're going to get is limited safety improvements at the A6024 and highly likely the rest will be reduced speed limits and enforcement measures because the National Park is an insurmountable obstacle. In this context a SPUI at the end of the M67 is a vast improvement on what's there now and would complement the limited bypass works at Mottram whilst providing a more reliable interchange for the traffic already using it without inviting shedloads more onto it. It's only a stopgap if you believe in a never ending increase of driving, which is contrary to transport policy - or it should be if you still want a planet to bother with.

Vastly maybe not, but further A628 improvements are pretty inevitable I'd have thought. For starters the residents of Hollingworth and Tintwistle are not going to be too happy with the extra traffic resulting from their neighbour's bottleneck getting bypassed and will want the same.

As for Denton, I don't see how one can in the same breath say that increasing traffic is ending the world and that we should build an SPUI that will increase traffic. A funky junction design doesn't give you a discount on the radiative forcing effect of CO2 emissions.

This isn't the gotcha you think it is. The SPUI doesn't massively increase traffic, it manages what's already using an overloaded emissions hotspot much better and capacity is a side effect of improved safety and efficient operation. That's the whole point. The fact you can fit a load of SUDS and environmental enhancements around the SPUI helps mitigate the use of concrete. The roundabout offers no such opportunity being an open canyon with concrete bridges, and it also has safety problems due to the abysmal design of the spiralling and dubious free-flow turn lanes.

Safety upgrades create capacity by reducing the number of cock-ups that can occur, but their sole aim is to improve safety. Anything else is a bonus. Whereas people who design purely for capacity sacrifice safety and get neither.

[Peter Freeman]

Rather selectively-edited quotes without changing context -

The A628 is never going to be vastly improved beyond what's there now despite TfN's dreaming of a mega tunnel, the best you're going to get is limited safety improvements at the A6024 ... In this context a SPUI at the end of the M67 is a vast improvement on what's there now and would complement the limited bypass works at Mottram whilst providing a more reliable interchange for the traffic already using it without inviting shedloads more onto it. It's only a stopgap if you believe in a never ending increase of driving, which is contrary to transport policy - or it should be if you still want a planet to bother with.

... further A628 improvements are pretty inevitable I'd have thought.

As for Denton, I don't see how one can in the same breath say that increasing traffic is ending the world and that we should build a SPUI that will increase traffic.

The SPUI doesn't massively increase traffic, it manages what's already using an overloaded emissions hotspot much better and capacity is a side effect of improved safety and efficient operation. ... The roundabout ... has safety problems due to the abysmal design of the spiralling and dubious free-flow turn lanes.

Safety upgrades create capacity by reducing the number of cock-ups that can occur, but their sole aim is to improve safety. Anything else is a bonus. Whereas people who design purely for capacity sacrifice safety and get neither.

My motivation for suggesting a SPUI at Denton actually was to increase capacity. I think severe congestion points (on main roads, not everywhere) should always be addressed. In fact I think congestion should be the main determinant of where we concentrate improvement efforts (which is why I often consult Google Maps' 'typical traffic' layer).

Safety is important, and must be a priority element of design. Small slow-speed roundabouts are safe. Large multi-lane roundabouts are not safe - and ironically, they're nowhere near as capacious as you'd think. SPUI safety is probably in-between. Bryn's J24 design is better than most in this respect: nice kerbed guidance islands, not just paint.

Bryn says that capacity is a side benefit of a safety improvement. I'm sceptical of that, but I'm sure that safety is a side-benefit of capacity improvements that follow good design principles. Congested roads are not very safe (eg. see how one accident often leads to others).

I have many points of agreement with both Bryn and Jackal. I share the wish for better public transport, but not its usage being compelled by creating or ignoring road congestion. Also, buses are an important PT mode, and they use the same roads as us.

Bryn believes that active travel, especially cycling, has an important role to play. I don't. I love riding my bike, recreationally. I have known people who commute to work by bike, but not many, and I just can't see that changing. Jackal has a fascination with detailed road, especially motorway, design. So do I. I enthusiastically follow progress in Australia's developing network. It's absorbing, even exciting, but I feel some guilt because I know it's only a part of the answer.

Bryn and Jackal both mention car emissions. They are a problem, but that will be solved within a decade or two. Our planet has many more climate, and other environmental, issues than that one. Ultimately, we're not a sustainable species, in so many ways.

Regarding road design trends, Bryn is right that a SPUI at Denton and a DDI at J7 would, by their 'before-your-very-eyes' demonstration of how interchanging traffic can flow so much better, set UK onto a much more enlightened and productive path. I won't be holding my breath.

Also on road design, UK could shed some of its conservatism and tradition. SPUIs and DDIs are good examples, but how about ramp metering, appropriate carriageway width, rational selection between free-flow and signalisation (riddle: "when is a service interchange not a service interchange?"), etc. Ironically, NH were brave (gung-ho?) about ALR, which I regard as progressive, but it seems to have landed them in trouble. Radical usage of tunnelling to solve otherwise intractable problems might help too, as it does for AU, but perhaps UK can't afford that.

ps. What is SUDS ?

(edited only to correct GE to GM)

[Peter Freeman]

... my experience of almost all of the M60 north-eastern quarter traffic light junctions are that they are all woefully underpowered

UK has a habit of under-powering its traffic signal intersections, even new builds, and even where there's space. The two sets on the proposed Mottram Bypass are a rather topical example.

Those on the M60 NE quadrant look under-powered to me (ie. stop lines don't have sufficient lanes), but actually that stretch doesn't appear to have major congestion, until you get close to Simister or Denton. It's unusual in having a predominance of signalised interchanges instead of GSRs, so there is the ability to address those issues, if and when necessary.

[Bryn666]

SUDS is sustainable urban drainage, so more planting, grassed areas, and general surfaces that can absorb rainwater instead of increasing the hard landscaping which contributes to flash flooding.

Australia seems to be aware of the need for this stuff without dressing it up in fancy acronyms but we think trees and things that make an area worth living in are "maintenance liabilities"...

[Chris5156]

I take it the vehicle counts back up the assertion that m67-m60n is the dominant flow?

I always assumed most traffic using the woodhead/snake corridors would use the southern half of the M60 and anyone going north would go up to the M62.

And, as much as I’m not suggesting it’s the same thing, my experience of almost all of the M60 north-eastern quarter traffic light junctions are that they are all woefully underpowered

Worth saying the strategic flows might tend to be from A628 > M67 > M60 southern side, but the majority of traffic passing through Denton Island won't have come over the Pennines, it'll be local traffic from Marple, Hyde and Denton going to other places in Greater Manchester. As such quite a lot will be heading up the M60 towards Ashton, Oldham, etc.

[jackal]

I'd rather structural megabucks were spent on lessening the severity of the clockwise bend at M60 J25 to get rid of the blind curve which even a 50 limit and SPECS does little to mitigate. NH are desperate to get rid of the right hand lane gain because "non-standard" yet seem perfectly content to keep that bend. Just shows how skewed their priorities are in terms of safe systems design.

I don't know about NH's plans, but the recentish version of the Hazelgrove bypass had a neat redesign of the M60 at J25, with both the offside merge and tight clockwise turn removed. They are linked as it's the bridge for the onslip that constrains the curve. The less said about the design of the link road itself (starting with a hamburger, natch) the better.

[Peter Freeman]

I'd rather structural megabucks were spent on lessening the severity of the clockwise bend at M60 J25 to get rid of the blind curve which even a 50 limit and SPECS does little to mitigate. NH are desperate to get rid of the right hand lane gain because "non-standard" yet seem perfectly content to keep that bend. Just shows how skewed their priorities are in terms of safe systems design.

I don't know about NH's plans, but the recentish version of the Hazelgrove bypass had a neat redesign of the M60 at J25, with both the offside merge and tight clockwise turn removed. They are linked as it's the bridge for the onslip that constrains the curve. The less said about the design of the link road itself (starting with a hamburger, natch) the better.
M60 J25 realignment - Copy.JPG

That M60 bend doesn't look very sharp to me. In Melbourne we have some sharper, on ALR, with the same 80km/hr limit. Couldn't most of the 'blindness' be cured simply by clearing that close vegetation?
Right hand nb merge: interesting tiger-tailing there, which is quite inventive - doesn't it work well? Without it, the merge could occur earlier, increasing the distance to J24, so allowing more lane-changing time - maybe. Alternatively, 50mph mainline limit for the merge duration, and meter the ramp.
"... neat redesign ..." - joking? The current J25 is ridiculous (two adjacent roundabouts to interchange one motorway with one low-quality S2 local road (A560)!! The neat redesign just changes their shapes, widens their circulatories, and throws in hamburger cut-throughs. For goodness sake !!
Hazel Grove Bypass: is this scheme approved/pipelined/in a RIS/shelved? Do we have a topic or a link-to-layout for it? Edit - oh yes, just saw it, in the Stockport thread.

[jackal]

^ Hence "neat redesign of the M60 at J25".

I guess you saw anyway from the Stockport thread, but the HG bypass was a local authority scheme that died when the government made clear they wouldn't fund it.

[Truvelo]

^ Hence "neat redesign of the M60 at J25".

I guess you saw anyway from the Stockport thread, but the HG bypass was a local authority scheme that died when the government made clear they wouldn't fund it.

So where does this leave J25 now? The layout will stay as it is permanently? And as for the bypass I assume the route will no longer be protected from development so someone will build tin sheds to prevent it ever being resurrected.

[jackal]

As far as I know the route is still protected. Re: J25, there is a Manchester SE junction scheme though details are sketchy: viewtopic.php?p=1210705

[Peter Freeman]

^ Hence "neat redesign of the M60 at J25".

Oh, sorry, I see the limited scope of your comment now.

Removing the offside merge, and (only slightly) alleviating the curve, at the cost of building one bridge and fairly extensive carriageway re-alignments, was worthwhile as part of that HG Bypass project, but hard to justify as standalone. I suggest J25 should be left as-is unless it can be addressed as part of some other improvement.The only projects at all likely are M60 widening or a re-awakening of the bypass (A6(M)/A555 extension).

If/when that time comes, there appears to be much space at that location and all the way southwards to J27. That would allow for a thoroughly modern re-think. The under-used apertures under the Lingard Lane bridge offer opportunities for braiding or extended ramps north of J25 (as already exist, and could be further exploited, southbound between J25-26-27).

I'm intrigued by the 6-way signalised crossover here . Brilliantly pragmatic, and appears not to suffer or cause any congestion (the queues onto M60 are not its fault).

(I suppose all this should go in another topic}

[jackal]

^ Hence "neat redesign of the M60 at J25".

Oh, sorry, I see the limited scope of your comment now.

Removing the offside merge, and (only slightly) alleviating the curve, at the cost of building one bridge and fairly extensive carriageway re-alignments, was worthwhile as part of that HG Bypass project, but hard to justify as standalone. I suggest J25 should be left as-is unless it can be addressed as part of some other improvement.The only projects at all likely are M60 widening or a re-awakening of the bypass (A6(M)/A555 extension).

If/when that time comes, there appears to be much space at that location and all the way southwards to J27. That would allow for a thoroughly modern re-think. The under-used apertures under the Lingard Lane bridge offer opportunities for braiding or extended ramps north of J25 (as already exist, and could be further exploited, southbound between J25-26-27).

I'm intrigued by the 6-way signalised crossover here . Brilliantly pragmatic, and appears not to suffer or cause any congestion (the queues onto M60 are not its fault).

(I suppose all this should go in another topic}

There's little point widening up to J27 if you're not also widening the other side of it through Stockport, where the M60 is busier. As discussed previously, this could be done as the viaduct arches are actually massive, and it's only the pointless fences and walls inside them that constrain things.

[wrinkly]

Attempted legal challenge by CPRE

https://www.manchestereveningnews.co.uk ... d-25997381