M20 - Cork to Limerick [preferred route chosen; in design - phase 3]

Note that it’s the preferred option (or presumably mix of options) as opposed to preferred route that is due in March.

It did finish last Autumn but the route selected at that time did not sit well with powers that be. Consultants sent back to drawing board.

Well considering that we have three Green parties in Government, rather than just one (which was therefore supposed to have one-seventh of the influence) with the way both parties sold their souls to get into power for one more go of it, I'm not getting my hopes up.

The Nimby groups are much, much worse than they were and the judicial review line is far more of a sword than it used to be.

Don't forget, the M9/8/7/6/1 were all built without MASSIVE Nimby problems. Only the M3 and the Slane Bypass really got hit with issues (as well as the original Galway bypass). Nowadays pretty much every scheme gets bogged down.

Why would a new motorway and upgraded rail line be better than a new road and new rail line?

Why wait? Either we get the Cork to Limerick M20 that we have been promised for years, or it is effectively canned by the Green Minister for Transport to comply with newly-introduced Green restrictions on road investments which the Greens demanded as a condition (among others) of going into coalition.

If it's the former, we get a pleasant surprise in March and a sense of relief that someone somewhere is still capable of making sensible decisions on infrastructure investment, and if it's the latter we will have gotten a head start on the justified complaints.

It is. The traffic figures speak for themselves.

Actually, there’s a possibility that the whole thing will be Type 1 DC, but that it will be the middle section, not the ends, that ends up under motorway restrictions if there’s a split. There’s lots of reasons not to have motorway regulations on a road with close-spaced junctions carrying a lot of commuter traffic. (See also N7, N25)

“It’s that simple”? No, it isn’t.

Before I start, I’ll say that I personally think the best approach is a Type 1 DC (what most people would call a “motorway”) for the whole length of the scheme, but that’s only for reasons of consistency; and I would expect the Cork end to be on green signs, not blue, because that’s what Cork County has done with all their other major approach roads.

On traffic numbers, however, there’s not a lot of justification for that position.

For example, now that Adare will be served by the new N69/M21 project, there is no traffic justification for any of the new-build N20 in Limerick to be a motorway (the already-built M20 serves Patrickswell). The original M20 plans had N20 here serving as part of a southern bypass of Adare, which would have produced enough traffic to justify a Type 1 DC. With Adare using M21 instead, you’ve got a road that serves only Croom and the very sparsely populated southern part of County Limerick - maybe 15,000 vehicles a day at the very most.

In this part of Limerick/Cork there is not a whole lot of diversionary travel - bad as N20 is, there really isn’t any better route than the current one (look at a map that shows mountains), so current traffic levels are pretty close to actual demand for North-South travel in this part of the counties.

A 2+2 from the M20/M21 interchange all the way to Mallow would be well within capacity (pre-pandemic peak traffic levels are around 11,000 - less than half the capacity of a 2+2), and it would be considerably cheaper to build than a motorway.

If I was responsible for getting value from the transport budget, I would seriously consider the 2+2 section, as that would allow me to use the savings for projects elsewhere on the network, and by doing that I could move forward other projects in Cork and Limerick. (Upgrading N71 from Bandon to Cork, or N24 Limerick Junction to Limerick, for instance).

Traffic numbers on the N20 are not reflective of the true figure of potential motorists driving this route as many Cork->Limerick drivers do not use the route at all. Instead, they use the M8 and R513. Look at the 2019 figures between the two Mitchelstown junctions (TMU M08 105.0 S & TMU M08 100.0 S) and you see that almost six thousand cars join/leave the motorway at the junction. Put that with anecodatal evidence reported on here, and from people I know, who never use the N20 simply because it's too slow, awkward and unsafe.

Furthermore, there is induced demand - traffic is attracted to better roads. A perfect example of this is the M17 motorway. It did not do one part of what its builders hoped it would do and take (the bulk of) traffic off the N17 for Galway. Instead, what it did do, is re-route a whole lot of Mayo->Dublin traffic down this route. Which is great news for all the back roads in Mayo that people were taking previously. Similarly, a tradesman I know in North Galway took a job in Limerick for a few months - he told me that he would never have considered it had the motorway not been built.

The same applies for the M20. Its construction will allow for more possibilities for people. Consider someone from Buttevant who has been offered a job in Raheen but is thinking of not taking it because they can't afford to rent in Limerick. With the M20, that becomes a reality for them. A safe, reliable journey into the outskirts of Limerick.

I would not normally be in favour of an absolutist, all-or-nothing approach to things, but in the case of the M20, it applies. In fact for me, it's simpler - it's not M20 or nothing. It's M20 or M20. Patrickswell to Blarney is only 80km - not 800. My concession to gradualism for me would be to do the Croom bypass upgrade last, since it's a pretty good road. Leaving Banoge to Blarney, a distance of 70km. And the highest priority is the dangerous 40km between Banoge and Mallow.

Let's not do an Ireland of the 1970s and half-ass this job now, like the 2+1 sections on the existing road. Build it once and build it right.

@cjpm - Cyclists are not permitted to use the vehicle carriageways of a 2+2 dual-carriageway, but the 2+2 road-type requires that a parallel cycleway must be provided. Private accesses are forbidden on 2+2 roads.

Agricultural machinery will end up on the road regardless. All modern tractors can reach the minimum speed required to use a motorway.

@serfboard Look at a relief map. The Galty mountains means there no other route but N20 between North Cork and South Limerick. Traffic leaving at Mitchelstown is not heading back towards N20 - at peak, 3,000 AADT on N73 between Mitchelstown and N20. Traffic on M8 and N24 does not drop either side of Cahir. Very, very few people are using M8 as a replacement for N20.

The difference between a type 1 DC and a 2+2 for your imaginary commuter is not really that significant. That trip from Buttevant to Raheen means driving on 40 km of road that is yet to be built. At a steady 100 km/h on a 2+2 that will take 24 minutes, at 120km/h it’s 20 minutes. There will be little to no congestion on either road type until the N21/M20 interchange.

Again, though, my preference is for Type 1 DC all the way through, but there are arguments for a 2+2 that are not just “doing it on the cheap”.

But it is.

A lot of traffic from North West Cork avoid the N20 too. I personally know a few people who detest the Cork Mallow section.