N11/N25 - Oilgate to Rosslare Harbour [route options published]

Chris_5339762 · 23-06-2021 11:58am

I think 2+2 to the port could be justified, on the grounds of a good connection, with overtaking opportunities for the number of lorries coming off. Also, a safer driver for them.

Just doing single carriageway to the port would be ok, but I think 2+2 would be justifiable in this case, even with lower traffic numbers than perhaps required.

KrisW1001 · 23-06-2021 12:31pm

Yes, I do favour building 2+2 from Wexford down to the port, even though it’s overkill on volume. Safety is the main reason. Car drivers do stupid, dangerous things when they’re behind HGVs, campers or caravans, and the road to a ferry port always has lots of these on it.

Pete_Cavan · 23-06-2021 12:32pm

I wouldn’t be surprised if there was no additional motorway in this project at all. Could be something like 2+2 all the way as far as the R740 and SC the final few km from there. The penultimate junction could be with the R740 which would see all local traffic for Rosslare Strand, Tagoat, etc. turn off and SC could then suffice as it would only serve traffic to Rosslare Harbour.

hi5 · 23-06-2021 1:44pm

KrisW1001 wrote: »

Yes, I do favour building 2+2 from Wexford down to the port, even though it’s overkill on volume. Safety is the main reason. Car drivers do stupid, dangerous things when they’re behind HGVs, campers or caravans, and the road to a ferry port always has lots of these on it.

Yep, drivers do crazy overtaking things when they think the're going to miss the ferry!

According to that video they will use the existing road in places, so it won't be motorway as there is no alternative road for non motorway traffic.

Chris_5339762 · 23-06-2021 1:59pm

True actually. Unless they build parallel roads for that section.

I'd be quite surprised if they don't do motorway to the northern end of the Wexford bypass though. It seems a logical place to stop it.

Edit: Or maybe the N25 junction as thats where the traffic level would change? Then you'd need parallel roads on that section of the Wexford bypass.

KrisW1001 · 23-06-2021 2:24pm

I think we’ll see a motorway continuing the M11 from Oilgate, crossing the Slaney to the west of the existing N11 bridge, and terminating pretty much where the existing N11 does now, at Ballindinas:

The chosen option is an online upgrade from there, following the N25 bypass of Wexford town, and that pretty much guarantees that it won’t be a motorway, so it’s most likely to be at most a 2+2 for the entire N25 section from Wexford to Rosslare.

There’s no M25 on the cards here.

marno21 · 23-06-2021 2:30pm

The Foynes link on the M21 scheme is 2+2 and would be much quieter than this. A fair good sign that this will be DC pretty much the whole way to the port.

Motorway as far as the N25 junction wouldn’t surprise me either. Traffic was pushing the upper limit for a 2+2 before Covid/Brexit.

The big question is what they’ll do at the N25 junction. 2+2 standards would advise roundabout or compact GSJ. This needs to be a grade separated roundabout with the volume of traffic using it and the distribution of traffic across the 4 routes feeding into it. A direct slip road from the N25 north to the N25 west would help a lot too.

KrisW1001 · 23-06-2021 2:43pm

I suspect it would be at least a grade-separated roundabout here, as this would also be a junction on M11.

N25 West remains a single-carriageway road here, but I hope they’re planning to make the tie-in at least a 2+2: N25 from here to the New Ross bypass is very wide, and could easily be upgraded to a 2+2 in future.

Chris_5339762 · 23-06-2021 2:44pm

General roundabout or a 3 level stack A La Rathmorrissy maybe?

Shame the Barntown bypass seems to have disappeared from the plans, there was an opportunity there.

Pete_Cavan · 23-06-2021 7:41pm

If motorway was extended to the N25 junction, wouldn't that pretty much guarantee an at grade junction anyway? They prefer to have a clear designation between motorway and DC, like at the northern end of the M3.

marno21 · 23-06-2021 8:02pm

Pete_Cavan wrote: »

If motorway was extended to the N25 junction, wouldn't that pretty much guarantee an at grade junction anyway? They prefer to have a clear designation between motorway and DC, like at the northern end of the M3.

The New Ross bypass (Type 1 -> Type 2) is an example of the opposite of this.

marno21 · 23-06-2021 8:03pm

Chris_5339762 wrote: »

General roundabout or a 3 level stack A La Rathmorrissy maybe?

Shame the Barntown bypass seems to have disappeared from the plans, there was an opportunity there.

My guess would be a grade separated roundabout ala N18 J9

Pete_Cavan · 23-06-2021 8:42pm

marno21 wrote: »

The New Ross bypass (Type 1 -> Type 2) is an example of the opposite of this.

Different road types but no change in designation, speed limit, restrictions, etc. right?

spacetweek · 23-06-2021 9:21pm

Pete_Cavan wrote: »

If motorway was extended to the N25 junction, wouldn't that pretty much guarantee an at grade junction anyway? They prefer to have a clear designation between motorway and DC, like at the northern end of the M3.

There are cases of this in Ireland and the UK but they are non-standard features on a motorway. You aren't supposed to end a motorway on a roundabout.

marno21 · 24-06-2021 9:22am

Pete_Cavan wrote: »

Different road types but no change in designation, speed limit, restrictions, etc. right?

Yes fair point, but the greater underlying point I was trying to make is that the N11/N25 roundabout at present is a congested mess at peak times let alone introducing a motorway into the equation. Making it free flow north/south, with a grade separated roundabout for east/west movements and a free flow left slip lane for the N25 north -> N25 west movement would be a sensible arrangement.

Pete_Cavan · 24-06-2021 9:41am

spacetweek wrote: »

There are cases of this in Ireland and the UK but they are non-standard features on a motorway. You aren't supposed to end a motorway on a roundabout.

That is not true. Our most recently built motorways end at roundabouts; M3, M11 and M17. In the case of the M3 and M17, the routes continue as 2+2 yet roundabouts were still installed. The M6 and M9 also end at roundabouts.

Pete_Cavan · 24-06-2021 9:46am

marno21 wrote: »

Yes fair point, but the greater underlying point I was trying to make is that the N11/N25 roundabout at present is a congested mess at peak times let alone introducing a motorway into the equation. Making it free flow north/south, with a grade separated roundabout for east/west movements and a free flow left slip lane for the N25 north -> N25 west movement would be a sensible arrangement.

Yes but recent projects suggest that there is a reluctance to have motorway run straight into 2+2 (M3 and M17) so motorway south of the existing M11 might mean a roundabout at the N11/N25 junction. If it was 2+2 south of the existing M11 a junction layout like you describe could be more likely.

KrisW1001 · 24-06-2021 10:28am

There’s no rule that says motorways can’t terminate at a roundabout. Junction type is a function of the expected traffic volumes.

Currently M8, M9, M17 end at a standard at-grade roundabout. M8 will be replaced, but the other two are very likely to remain as-is, as they don’t present problems.

spacetweek · 24-06-2021 11:12pm

Pete_Cavan wrote: »

That is not true. Our most recently built motorways end at roundabouts; M3, M11 and M17. In the case of the M3 and M17, the routes continue as 2+2 yet roundabouts were still installed. The M6 and M9 also end at roundabouts.

I know, I said there were examples in Ireland. But internationally, it's a non standard feature. You'd never have the like in the USA or Germany for example.

marno21 · 24-06-2021 11:31pm

If you can build a motorway and terminate it at a roundabout with no issues whatsoever, it begs the question, do you need to be building a motorway at all?

If they terminate the M11 at an at grade roundabout with the N25 and the R769 it will be troublesome, as the existing junction is. It would be bizarre to do so.

Pete_Cavan · 25-06-2021 7:39am

marno21 wrote: »

If you can build a motorway and terminate it at a roundabout with no issues whatsoever, it begs the question, do you need to be building a motorway at all?

If they terminate the M11 at an at grade roundabout with the N25 and the R769 it will be troublesome, as the existing junction is. It would be bizarre to do so.

Nobody has said we need to build a motorway here, some here have decide that for themselves. AADT at Oilgate (just over 14k in 2019) doesnt suggest motorway is needed.

The M11 currently terminates at a roundabout (as do M3, M6, M9 and M17). Terminating at a roundabout doesn't beg any questions whether you need the motorway at all (unless you think the aforementioned motorways shouldn't have been built as such). The standard here has been to terminate motorways at roundabouts, even when the road continues as 2+2. This is the case for the M3, M17 and is the plan for the M21. Based on this, it is also likely for the Oilgate to Rosslare project.

My point is that, assuming the motorway is to terminate at a roundabout (as is standard), it would be better to end the motorway where it currently ends and continue the N11 south as 2+2. With 2+2 both north and south of the N11/N25/R769 junction, that junction might actually be built with grade separation as you described before. By having the transition from motorway to 2+2 further north, a roundabout wouldnt be needed at the N11/N25/R769 junction.

KrisW1001 · 25-06-2021 10:34am

marno21 wrote: »

If you can build a motorway and terminate it at a roundabout with no issues whatsoever, it begs the question, do you need to be building a motorway at all?

Yes, if there’s a plan to extend it in future.

M9’s strange end would eventually be replaced by a section of an N9/N24/N25 interchange when N24 is upgraded. Right now, grade separation is unnecessary because N24 is single-carriageway, and the replacement N24 may not even be there in the end. An at-grade junction allows N24 movements now without trying to second-guess the route of the future N24 or risking a white-elephant junction-to-nowhere.

The reason you don’t see roundabout terminations of US freeways is because as a rule, US highway engineers doesn’t use roundabouts for anything in any circumstance. There are however many motorway-type roads that end at what are effectively T-junctions, and there are several freeways that join other similar controlled-access roads at cross intersections with lights.

spacetweek · 25-06-2021 9:17pm

KrisW1001 wrote: »

There are however many motorway-type roads that end at what are effectively T-junctions, and there are several freeways that join other similar controlled-access roads at cross intersections with lights.

Well that is news to me, I've never seen it.

circadian · 25-06-2021 9:22pm

Chris_5339762 wrote: »

General roundabout or a 3 level stack A La Rathmorrissy maybe?

Shame the Barntown bypass seems to have disappeared from the plans, there was an opportunity there.

I just searched that and I have to say its probably the finest piece of road design I've seen in Ireland.

KrisW1001 · 28-06-2021 10:08am

spacetweek wrote: »

Well that is news to me, I've never seen it.

There used to be a lot of them even on the Interstate network, but they’re being removed as routes are extended. But here’s one that’ll probably be there forever, as there’s nowhere further to go: the southern terminus of Interstate 37 in Corpus Christi, TX; traffic lights at a cross intersection.

https://www.google.com/maps/@27.8015457,-97.3950367,3a,75y,246.06h,99.62t/data=!3m6!1e1!3m4!1s0mUsXaBYvVHkfO5D-ec1bg!2e0!7i13312!8i6656

... That’s basically the US equivalent of ending on a roundabout.

State highway networks in the US are much more likely to have at-grade terminii, as each state Dept of Transportation has more freedom when designing these roads.

marno21 · 04-08-2021 6:20pm

Options Selection Report has been published.

https://oilgate2rosslareharbour.ie/wp-content/uploads/2021/07/Option-Selection-Report-229100548-MMD-0000-XX-RP-C-0017_P3.pdf

The scheme will be a Type 1 dual carriageway from Oilgate to Rosslare Harbour. Likely designated M11 so the M11 will run the entire way to the port.

Chris_5339762 · 04-08-2021 8:37pm

Surprised at that, but I think its the correct decision. Motorway to the port for sanity and HGV reasons.

You're right that it'll probably end up M11 to the port. I can't see them having any M25, unless they make it M11 to the M11/N25 junction and then do N25 from there, but Type 1 DC. They seem to not want little bits of motorway classification.

Pete_Cavan · 07-08-2021 11:46am

https://www.boards.ie/discussion/comment/117706376#Comment_117706376

I had a look at the report, it doesn't say the road will be Type 1 DC, nor does it recommend a road type. It assumes Type 1 but also says the cross section will be determined at a later stage. The assessment and corridor widths are based on the highest and most difficult to achieve standard, they can then be reduced later if required.

8.10.4 Description of Proposed Scheme Infrastructure

The N11/N25 Oilgate to Rosslare Harbour scheme is currently at the initial stages of the design process. The proposed cross section of the scheme will be determined in the subsequent stages of the TII project management phases. However indicative cross sections have been used for the assessment at this stage. For Option 13 the online management option a Type 2 Dual Carriageway has been assumed for the section south of Oilgate to the Rosslare Road Roundabout, the remained of the option maintains the existing single carriageway. For all other options a Type 1 Dual Carriageway has been assumed.

Even under section 9.1 Recommended Preferred Option, it only restates the assumption and does not recommend anything.

9.1.2 Design Standards

The TII Publications (Standards and Technical) were used for the design of the scheme.

For the purpose of option selection, a Type 1 Dual Carriageway cross section as per DN-GEO03036 and CC-SCD-00006 was utilised. A design speed of 120kph was utilised for the alignment design, which was undertaken in accordance with DN-GEO-03031

hometruths · 22-08-2021 1:13pm

Was looking at the interactive map and had a query...

This the preferred route just south of the N25 roundabout at Drinagh, south of Wexford town. Presumably at the point where it cross the N25 here the new road will be lifted and built on a flyover over the existing road? Does not seem to be any other likely option I can see?

Chris_5339762 · 22-08-2021 8:48pm

Existing road could go on a flyover instead - build the flyover next to the current N25, divert traffic onto it, then build the new road underneath.

I think it all depends on local topography, junction etc.

N11/N25 - Oilgate to Rosslare Harbour [route options published]

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