[IRL] M20 Cork to Limerick Motorway EIS published

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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by odlum »

The Devil's Armpit wrote: Thu Mar 14, 2019 21:33 How these major works are funded would be an interesting read
They are funded mostly through central government funds or occasionally public private partnerships. This is not a PPP scheme though so funding is from the govt.

The EIB could also choose to invest in some projects. We don't get what we use to for projects from the EU anymore.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Euan »

It will be good to eventually see the M20 completed. Amongst the non Dublin based motorway projects in Ireland this one would probably be the most useful with Cork and Limerick being the 2nd and 3rd largest cities in the Republic respectively...

...And of course it would complete a small segment of the longer term Atlantic Corridor proposals, although the most important part running from Cork to Galway would be near enough complete.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by si404 »

Berk wrote: Thu Mar 14, 2019 22:55I keep hearing that Scotland has 7 cities, but what order do they come in?? :?:
by population it goes: Glasgow, Edinburgh, Aberdeen, Dundee, Inverness, Perth, Stirling

by more abstract measures, such as the stuff looked at for the granting of city status, Edinburgh would probably be #1 and Aberdeen/Dundee and Perth/Stirling might swap places, but none of that matters for the OPs point.

So the cities linked are 1-2 (M8), 2-8 (M90), 2-9 (M90) and 1-9 (M80).

The key reason why Glasgow/Edinburgh won't be linked by motorway to Dundee and Aberdeen is one of the law of diminishing returns. It's all dual carriageway currently with many junctions grade-separated - unlike the single-carriageway and often low-quality N20 - the piecemeal upgrade to mid-quality makes a wholesale high-quality upgrade less likely. Why upgrade the route to motorway, when right turns can be removed, a few more junctions grade-separated, etc for far less cost? See also the A1 Peterborough-Blyth (which has slightly more traffic). Dundee could get a motorway standard bypass, but would Perth-Dundee get upgraded to join them up? Probably not.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Euan »

si404 wrote: Fri Mar 15, 2019 09:45 The key reason why Glasgow/Edinburgh won't be linked by motorway to Dundee and Aberdeen is one of the law of diminishing returns. It's all dual carriageway currently with many junctions grade-separated - unlike the single-carriageway and often low-quality N20 - the piecemeal upgrade to mid-quality makes a wholesale high-quality upgrade less likely. Why upgrade the route to motorway, when right turns can be removed, a few more junctions grade-separated, etc for far less cost? See also the A1 Peterborough-Blyth (which has slightly more traffic). Dundee could get a motorway standard bypass, but would Perth-Dundee get upgraded to join them up? Probably not.
I think that is probably one of the main reasons for there being no motorways linking Aberdeen and Dundee to the Central Belt with what later became the A90 being dualled the whole way between the two cities. In a similar context, I suspect that there would not be as many motorways crossing Ireland now had the existing main roads been dualled or at least substantially upgraded earlier on. The N20 would only be one example of this sort of idea, I think many parts of the N7 and N8 were also left unimproved for many years before the M7 and M8 were built.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by bothar »

Euan wrote: Fri Mar 15, 2019 22:23 I think that is probably one of the main reasons for there being no motorways linking Aberdeen and Dundee to the Central Belt with what later became the A90 being dualled the whole way between the two cities. In a similar context, I suspect that there would not be as many motorways crossing Ireland now had the existing main roads been dualled or at least substantially upgraded earlier on. The N20 would only be one example of this sort of idea, I think many parts of the N7 and N8 were also left unimproved for many years before the M7 and M8 were built.
As stated above, the mediocre is the enemy of the excellent.
You have a similar problem in NI where the A1 might have been an appropriate design in the 1960s but it is well below par now.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Owain »

bothar wrote: Fri Mar 15, 2019 22:33As stated above, the mediocre is the enemy of the excellent.
You have a similar problem in NI where the A1 might have been an appropriate design in the 1960s but it is well below par now.

Not least this monstrosity:
Screenshot (21).png
From Belfast, the logical way to access the A1 for Dublin would be to simply turn off at J7 and join it. However, the signage makes absolutely no mention of that, and tells you to carry on along the motorway for Dublin!

It's not until J8 that signage tells you to turn off for Dublin, sending you along a funny little link road instead of directly onto the A1.

Not only does the signed route take you a mile or so out of your way, but the proximity of J8 to J7 can mislead the unfamiliar into thinking that they'll be staying on the motorway for quite a while after staying on at 7. There was at least one occasion when I almost missed the signed Dublin exit (by overtaking in lane 2, thinking that it would be several more miles to my exit!), because of the whole set up.

If they really must send long-distance traffic via J8, I don't know why the A101 is not simply signed as "A1".
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by AndyB »

Dear me. Someone hasn't noticed the double fork signs at 1 mile and 1/2 mile to J7 ;)

J8 is part future proofing against a road from the north of J8 across to Knockmore Road, and part capacity diversion from the Sprucefield shopping centre maelstrom at J7. As built, J7 was a simple roundabout and trumpet, with no shopping centre.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by c2R »

Also, J7 is often more congested at the roundabout- it depends on the time of day/night I'm travelling through, but certainly on a Saturday afternoon you're best avoiding the roundabout at Sprucefield and joining /leaving at 8
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Johnathan404 »

I thought J7 had been designed deliberately, to create a Mecca for anybody who worships bad planning on the strategic road network.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Graham »

I'm a little curious as to why the road has been put in this corridor. A casual look a map suggests an alterative of building a motorway from Limerick to Cahir, with a spur motorway (cutting off the corner) between Mitchelstown and Tipperary. This would provide a good link between Cork and Limerick, and would also improve the route between Limerick and the towns (and ferries) in the southeast.

Is there something I am missing here? Would this overload the M8 south of Mitchelstown? Is the land north of Mitchelstown too difficult to build a road through?
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by odlum »

It's suppose to be a direct motorway from Limerick to Cork. Not sure they want it contaminated by Cork to Dublin just for regional connectivity reasons (the myth that all motorways go to Dublin).

It also provides more redundancy helping communties along the route to develop and be connected to the national network.

And...there is high terrain in the way on the M8 too between Mitchelstown and Cashel (although i'm not sure the extent to which this was taken in to account).


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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Euan »

Graham wrote: Sat Mar 16, 2019 16:57 I'm a little curious as to why the road has been put in this corridor. A casual look a map suggests an alterative of building a motorway from Limerick to Cahir, with a spur motorway (cutting off the corner) between Mitchelstown and Tipperary. This would provide a good link between Cork and Limerick, and would also improve the route between Limerick and the towns (and ferries) in the southeast.

Is there something I am missing here? Would this overload the M8 south of Mitchelstown? Is the land north of Mitchelstown too difficult to build a road through?
I doubt it would be numbered M20 if it had been planned to link Limerick to Cahir, i.e. along the corridor of the N24.

For a Limerick - M8 connection this would be the most sensible route to take, but for Limerick - Cork traffic it would be a big detour compared to the route of the N20.

Odlum's right about the difficult terrain at Mitchelstown - I doubt engineers would be keen on ploughing through the Galtee Mountains which would restrict the route of a potential motorway to the point that it would either only be useful for ferry traffic or Cork traffic, but not both. I doubt there is an easy way for this project to improve connections to the SE ports while fulfilling the original purpose of linking Limerick to Cork.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by odlum »

Ironically enough the N24 between Limerick and Waterford is also due to be upgraded in the future. I have read elsewhere at least part of this route could be upgraded to a motorway! But that's a long way out timewise.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by jackal »

The preferred route for the catchily named N/M20 Cork to Limerick has been published. There's a 500m wide corridor for the route but no detailed design yet. The map is here, and here's the description from the brochure:
The preferred option commences just south of the Blarney junction and remains largely online to maximise
the reuse of the N20 until it diverges eastward near Mourneabbey. Remaining to the east of the N20 it
crosses the River Blackwater, the N72, the N73 and the River Awbeg as it bypasses to the east of Mallow
and Buttevant until it converges with the existing N20 north of Buttevant. It then remains close to the N20
until it diverges westwards near Ballyhea, bypassing to the west of Charleville, before re-joining the N20
south of Croom. The preferred option reuses the N20 Croom Bypass and then diverges at Garranroe and
runs west of the existing N20 until it reaches its tie in point with the existing M20/N21 at Attyflin.
It will be 80km long, grade separated, and with 30%-40% online. It's not yet decided whether it'll be motorway or "Type 1 Dual Carriageway which is broadly similar to motorway but has a 100km/h speed limit" (Irish Times). Costs are indicated around 15m euros per mile for a 1-1.5bn euros total, with the earliest possible opening in 2030.

https://corklimerick.ie/
https://www.irishtimes.com/news/environ ... -1.4840091
https://www.independent.ie/regionals/co ... 04666.html
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Owain »

Euan wrote: Sat Mar 16, 2019 22:23
Graham wrote: Sat Mar 16, 2019 16:57 I'm a little curious as to why the road has been put in this corridor. A casual look a map suggests an alterative of building a motorway from Limerick to Cahir, with a spur motorway (cutting off the corner) between Mitchelstown and Tipperary. This would provide a good link between Cork and Limerick, and would also improve the route between Limerick and the towns (and ferries) in the southeast.

Is there something I am missing here? Would this overload the M8 south of Mitchelstown? Is the land north of Mitchelstown too difficult to build a road through?
I doubt it would be numbered M20 if it had been planned to link Limerick to Cahir, i.e. along the corridor of the N24.

For a Limerick - M8 connection this would be the most sensible route to take, but for Limerick - Cork traffic it would be a big detour compared to the route of the N20.
I'm not sure it would be a 'big' diversion! There are plenty of other examples in Britain and continental Europe where motorways have been planned so as to minimise the amount of construction and cost, by employing such diversions; and it's not like Ireland is a huge country with the diversion adding hundreds of kilometres to the journey.

In fact I've often looked at the map and wondered why there are so many north-south routes in relatively close proximity (M8, M9 and M11). I think I'd have gone for a single motorway from Dublin to Cork which followed the routes of the original N11, N30 and N25. A second could then have run down the centre of the country, from Mullingar to Waterford, crossing M6 and M7, and taking in the Kilkenny-Waterford section of M9. A third could then have pursued the Limerick-Cahir suggestion above, and taken in the bottom half of the M8, eventually becoming part of a longer west coast route also comprising M18 and M17.

Such a grid pattern would surely have been a more cost-effective way of doing things, and would have reduced the Dublin-centricity of the whole network without making it any more difficult to get from either Cork or Waterford to Dublin.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by bothar »

Owain wrote: Sat Apr 02, 2022 11:18 I'm not sure it would be a 'big' diversion! There are plenty of other examples in Britain and continental Europe where motorways have been planned so as to minimise the amount of construction and cost, by employing such diversions; and it's not like Ireland is a huge country with the diversion adding hundreds of kilometres to the journey.

In fact I've often looked at the map and wondered why there are so many north-south routes in relatively close proximity (M8, M9 and M11). I think I'd have gone for a single motorway from Dublin to Cork which followed the routes of the original N11, N30 and N25. A second could then have run down the centre of the country, from Mullingar to Waterford, crossing M6 and M7, and taking in the Kilkenny-Waterford section of M9. A third could then have pursued the Limerick-Cahir suggestion above, and taken in the bottom half of the M8, eventually becoming part of a longer west coast route also comprising M18 and M17.

Such a grid pattern would surely have been a more cost-effective way of doing things, and would have reduced the Dublin-centricity of the whole network without making it any more difficult to get from either Cork or Waterford to Dublin.
The problem with such a plan is that it is difficult to build it in segments. The original plan for Irish motorways was relatively modest and didn't involve a motorway to Waterford at all. Building it as it was allowed fairly short (inexpensive) bypasses be built and then connected to existing routes. Around 2000 the ambition greatly increased and projects like the M9 or M18 came on the radar as well as a continuous M8.

In the M20 case they are going to reuse some of the offline sections of S2 improvement in the past. In some cases that alignment runs close to the railway line and it is suitable for widening.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by jackal »

Owain wrote: Sat Apr 02, 2022 11:18
Euan wrote: Sat Mar 16, 2019 22:23
Graham wrote: Sat Mar 16, 2019 16:57 I'm a little curious as to why the road has been put in this corridor. A casual look a map suggests an alterative of building a motorway from Limerick to Cahir, with a spur motorway (cutting off the corner) between Mitchelstown and Tipperary. This would provide a good link between Cork and Limerick, and would also improve the route between Limerick and the towns (and ferries) in the southeast.

Is there something I am missing here? Would this overload the M8 south of Mitchelstown? Is the land north of Mitchelstown too difficult to build a road through?
I doubt it would be numbered M20 if it had been planned to link Limerick to Cahir, i.e. along the corridor of the N24.

For a Limerick - M8 connection this would be the most sensible route to take, but for Limerick - Cork traffic it would be a big detour compared to the route of the N20.
I'm not sure it would be a 'big' diversion! There are plenty of other examples in Britain and continental Europe where motorways have been planned so as to minimise the amount of construction and cost, by employing such diversions; and it's not like Ireland is a huge country with the diversion adding hundreds of kilometres to the journey.
I agree. But I'd suggest a direct route from the M8 at Mitchelstown to the M20 at Limerick. This is 47km compared to about 75km as-the-crow-flies for Cork to M20 along the N20 corridor. It would be barely less direct for Cork to Limerick. The route would go west of the Galty Mountains rather than through them (!).

A Limerick to Waterford motorway could use the Limerick to Mitchelstown section, then multiplex with the M8 for 15km, before cutting the corner for the N24 corridor towards Waterford. This would require an additional 60km of motorway, compared to 105km for the full N24 corridor motorway. So the total new motorway construction for Cork to Limerick and Waterford to Limerick is 47km+60km=107km, compared to 75+105=180km if you built along the N20 and N24 corridors.

The point about the M8 south of Mitchelstown maybe needing widening in this scenario is reasonable, but even if the whole lot would have to be done that would only be another 47km, so substantially less than the extra 73km of new motorway required with the N20/N24 corridors. The cost and environmental impact would be significantly lower due to the shorter distance and the fact it's widening rather than new motorway

A further advantage is that, as you cut the corner between the N24 and M8 south of Cahir, you get a perfectly serviceable Waterford to Cork motorway bundled in!

The main problem with the proposal is that the Limerick to Waterford route would be about 120km compared to about 105km with a motorway all along the N24 corridor. But the extra 15km is quite minor given the significant advantages.

(All distances are 'as-the-crow-flies' - obviously in reality both my suggestion and the N20/N24 route would be longer as they have to zig zag to avoid settlements etc.)
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by KrisW »

The above post does illustrate the difference in mindset behind how the Irish road network is planned versus the UK’s. Ireland uses a web rather than the “trunk and branch” approach of the UK.

The major reason for this is that, in Ireland, the motorways are components of the national route network, rather than a parallel network overlaid on it. In fact, there is no “Motorway Network” here at all, just roads within the National Route network that operate under motorway restrictions (legally, even the M50 Dublin orbital is National Route N50, even though every single metre of it is under motorway regulations). The National routes were set up much like the UK’s A-Road network, to provide the shortest safest routes between nationally-significant locations.

Once you understand that every Irish motorway is effectively what in the UK would be an Axxx(M) road, the reason for M8,M9 becomes much clearer: these aren’t trunk motorways to take long-distance traffic off the national network; they are the national network, provisioned for higher traffic. This also explains why, close to more populous areas, you will often see parallel 2+2 motorways separated by only 50~60km rather than a single 3+3: if the latter were in place, dragging these into one wider road, it would require new primary roads to be built to collect and distribute the traffic from the places that were served by the original routes (remember many Irish motorways were built as replacements for substandard single-carriageways, so there was no “old” road that could be used) - in the end it’s probably less cost and effort to build the two motorways, especially when “Motorway” here means a single 22 m wide paved surface with two running lanes per carriageway rather than 2x 15 m carriageways of 3 lanes, plus a median.

Finally, route-multiplexing is not used on the Irish national route network (it is on Regional and Local routes, though). Some may believe that there’s a multiplex of N14 onto N13 in Donegal, but that’s an online mapping error, and does not reflect what the signboards say when you drive there (the “N14” that emerges from the western junction of the N13 is, in reality, the N56).

On the actual topic, the N20/M20 corridor that will now proceed to plannin differs in a few places from the original 2009 plan: notably there’s no spur for the Limerick commuter town of Adare, as this will now be bypassed by an extension of the M21 as part of an access route to the deepwater port west of Limerick at Foynes. There are also no exact junctions, but the red-boxed places near the corridor map are clear indicators of where they are most likely to be.
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by bothar »

This project has advanced this week with the proposed corridor narrowed and the junctions identified.
The route is mostly offline, but subsumes the existing S2 bypasses and Blarney and Croom, with a rather tight junction on the latter.

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Interactive map
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Re: [IRL] M20 Cork to Limerick Motorway EIS published

Post by Enceladus »

bothar wrote: Thu Nov 30, 2023 17:24 This project has advanced this week with the proposed corridor narrowed and the junctions identified.
The route is mostly offline, but subsumes the existing S2 bypasses and Blarney and Croom, with a rather tight junction on the latter.

Project Website
Interactive map

This is real progress on a vital missing link in our motorway network that should have been built 15 years ago but fell victim to the crash and recession.

Of course, once the local rags....sorry newspapers got wind of the route corridor being narrowed, they printed that the planned motorway was now being halved in width with readers being up in arms with outrage over the long delayed Cork-Limerick M20 being now only S2. :roll: :shock: :twisted:
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