N18 - Limerick Tunnel & South Ring Road Phase II

KevR

Is the actual tunnel itself motorway spec? I thought the Southern Ring Road will be motorway spec but the tunnel won't be..

limklad

tech2 wrote: »

I will try and take a few of the Rossbrien interchange at some stage pass it enough times anyway, the mainline hasnt changed too much over the last few months so I will take some of those when some wearing course goes down. Ideally an aerial shot of the Rossbrien interchange would be the best!

Just looking at the clonmacken link road a few days ago, is there a real need for a concrete barrier for the median? I guess it has to be constructed like that due to the toll plaza.

I have only 1 gripe about this New Junction on the Motroway.
Going from Patrickwell to Dublin on the Rosbrien junction is an accident waiting to happen once the Tunnel is open. You have to go under the Bridge (no problem there) then negotiate a steep climb on a veer sharp left (270 degrees) and as you get onto the bridge and then you have a short distance to judge traffic flow to join it. It barely the length of the bridge. This access lane is way tooo short to join motorway speeds. Hey it is way too short to join normal 60kph speed at best.

I did several Test Runs, The max speed on the steep sharp left 270 degrees turn I manage without crashing into the barrier is 50kph and that was dangerous on dry road conditions. Most drivers are currently making that at 20-30kph and then you have to accelerate hard pick up to motorway speed to join while on the bridge and that provided that the driver in front of you is not scared. You need Sport types cars to do this successfully and that if there is a gap to join Traffic otherwise you have to fight for space between the bridge and slow lane on the narrow hard shoulder. Yet Traffic coming from Childers road have plenty of space to judge traffic before joining to match the Traffic speed.

It is a pity they did not leave the Roundabout that was there and use the Childers road access to the Motorway, it would be far safer and you will not be unnecessary wasting Car Fuel to Climb a steep bridge and do a rally car acceleration to join Motorway Traffic. On the Childers Road access you can gradually increase speed and safely to join a gap in Traffic on the Motorway as you have plenty of time to view the Traffic.

More precisely, This Road junction is a death trap waiting to happen. The NRA should have been shot for allow regulations of this kind of junction to be created.

Roryhy

This is the main flaw with free-flowing cloverleaf style junctions, their merits were being debated in one thread recently regarding the proposed junction of the m6 + m17/18

Zoney

limklad:

Not an ideal solution, but with the poor sightline on the mainline from the bridge rising up so sharply, I would guess that even the M7/N7 mainline may have a speed restriction starting on approach to the junction complex in both directions. So although the short merge is still an issue, I seriously can't see them planning to have 100/120 km/h traffic that you have to merge with.

Also I'm not sure those 50 km/h speed limit signs from J2 to J1 on the M20 will disappear once work is completed. Must get a photo of the on-slip onto M20 northbound from J2 - it looks rather silly the two M20 signs with "50 km/h" above them! Maybe I'm wrong and the speed restriction will only apply closer to J1 (although even so, it would nevertheless hardly make sense to allow traffic a limit of 120 km/h if entering M20 northbound from J2 - sure you'd hardly reach that before having to slow again).

Anyway, unlike Dock Road junction, traffic will probably flow smoothly enough through the junction complex.

spacetweek

limklad wrote: »

More precisely, This Road junction is a death trap waiting to happen. The NRA should have been shot for allow regulations of this kind of junction to be created.

Sometimes I think the solution to every problem on Boards is to shoot someone.

Thanks for pointing this out though.

Goofy

The tunnel is not the N7, it will be the N18. The N7 ends at the Rosbrien interchange. They probably didnt bother going though all the legal stuff to change the a small section of the N18 to M18, given that the tunnel and approach roads will have a limit of 80kph anyway.

Irish and Proud

limklad wrote: »

I have only 1 gripe about this New Junction on the Motroway.
Going from Patrickwell to Dublin on the Rosbrien junction is an accident waiting to happen once the Tunnel is open. You have to go under the Bridge (no problem there) then negotiate a steep climb on a veer sharp left (270 degrees) and as you get onto the bridge and then you have a short distance to judge traffic flow to join it. It barely the length of the bridge. This access lane is way tooo short to join motorway speeds. Hey it is way too short to join normal 60kph speed at best.

I did several Test Runs, The max speed on the steep sharp left 270 degrees turn I manage without crashing into the barrier is 50kph and that was dangerous on dry road conditions. Most drivers are currently making that at 20-30kph and then you have to accelerate hard pick up to motorway speed to join while on the bridge and that provided that the driver in front of you is not scared. You need Sport types cars to do this successfully and that if there is a gap to join Traffic otherwise you have to fight for space between the bridge and slow lane on the narrow hard shoulder. Yet Traffic coming from Childers road have plenty of space to judge traffic before joining to match the Traffic speed.

It is a pity they did not leave the Roundabout that was there and use the Childers road access to the Motorway, it would be far safer and you will not be unnecessary wasting Car Fuel to Climb a steep bridge and do a rally car acceleration to join Motorway Traffic. On the Childers Road access you can gradually increase speed and safely to join a gap in Traffic on the Motorway as you have plenty of time to view the Traffic.

More precisely, This Road junction is a death trap waiting to happen. The NRA should have been shot for allow regulations of this kind of junction to be created.

AFAIK, the junction was scaled down from the original plans - the 2 loops were supposed to be bigger (100m - 125m diameter). It's a disgrace that the reduced design was passed - as far as I'm concerned, the connection from the M20 to M7 towards Dublin should be a directional 3rd level flyover, with that loop scrapped altogether! :mad:

Regards!

sonyair

Goofy wrote: »

The tunnel is not the N7, it will be the N18. The N7 ends at the Rosbrien interchange. They probably didnt bother going though all the legal stuff to change the a small section of the N18 to M18, given that the tunnel and approach roads will have a limit of 80kph anyway.

I thimk you will find that it will be N7

http://en.wikipedia.org/wiki/N7_road_(Ireland)

Zoney

Indeed the N18 is likely to end at the Radisson, with the new mainline becoming N7 at the flyovers and the section from there into the city becoming an R road.

mysterious

Irish and Proud wrote: »

AFAIK, the junction was scaled down from the original plans - the 2 loops were supposed to be bigger (100m - 125m diameter). It's a disgrace that the reduced design was passed - as far as I'm concerned, the connection from the M20 to M7 towards Dublin should be a directional 3rd level flyover, with that loop scrapped altogether! :mad:

Regards!

I hear ya, i don't understand why we cant build proper interchanges, it just such a joke..............:rolleyes:

Seriously I just don't tolerate this crap. I'm sick of it.

limklad

spacetweek wrote: »

Sometimes I think the solution to every problem on Boards is to shoot someone.

Thanks for pointing this out though.

In Limerick we were promoted from stabbing to shooting idiots out of necessity to be in compliance with the Geneva conventions. It seems that stabbing was too cruel for the idiots.

Irish and Proud

mysterious wrote: »

I hear ya, i don't understand why we cant build proper interchanges, it just such a joke..............:rolleyes:

Seriously I just don't tolerate this crap. I'm sick of it.

I haven't seen the interchange in reality, but I would like to know how the ramp specs there compare with the NRA specs - I've seen NRA documentation on merge design before and saw a specific standard in relation to lane and taper lengths at motorway merge locations. The M50 junctions are pretty tight, but the M50 merges are decent though. If I think there are any discrepancies in relation to the Rossbrien Interchange, I'll be writing in to the NRA – there seems to be plenty of space, so there’s no excuse as far as I’m concerned! I would expect the N2 (Ashbourne South) loop specs at the very least for such an important junction!

Regards!

Goofy

sonyair wrote: »

I thimk you will find that it will be N7

http://en.wikipedia.org/wiki/N7_road_(Ireland)

http://www.nra.ie/RepositoryforPublicationsInfo/file,16998,en.pdf
See junction 30. The first thing you learn in college is to never reference wikipedia.

nordydan

Goofy wrote: »

http://www.nra.ie/RepositoryforPublicationsInfo/file,16998,en.pdf
See junction 30. The first thing you learn in college is to never reference wikipedia.

Which is more recent that this:

http://www.nra.ie/RoadSchemeActivity/LimerickCountyCouncil/N7LimerickTunnelLSRRPhase2/Map,16489,en.pdf

I do hope its N18, it makes a lot more sense (IMHO)

sonyair

Goofy wrote: »

http://www.nra.ie/RepositoryforPublicationsInfo/file,16998,en.pdf
See junction 30. The first thing you learn in college is to never reference wikipedia.

Well the nra don't provide accurate info
Wikipedia provides information on everything so you can reference anything you like even if your in college,
but it will be the N7

lukejr

Drove the M20 section (Driving East towards Dublin) for the first time since October, lots of work done since then. The M20 now splits left for Limerick City and right for Dublin.

The Dublin slip-road now links in (for 500m) with the completed section of the future M7/N7 Tunnel and continues on East until the roundabout (future Nenagh tie-in).

I was also on the Dock road in Limerick and the new round-abouts and slip-roads are almost complete, need to be surfaced. But progress is now progressing very quickly on this section.

How is the N18 tie-in progressing? It's been over two months since I have seen this in day light, would be interested to know what the tie is like at the moment.

Tech3

lukejr wrote: »

The Dublin slip-road now links in (for 500m) with the completed section of the future M7/N7 Tunnel and continues on East until the roundabout (future Nenagh tie-in).

Yeah the Rossbrien interchange is nearly complete, there is one ramp closed off- N7 East-M20 south but that is not needed until the whole scheme opens. It is done but no needed yet.

The M20 now splits left for Limerick City and right for Dublin.

This is temporary it will run towards the N69 interchange and tunnel when complete. City acess will be blocked off here from the M20 north.

brainyneuron

lukejr wrote: »

How is the N18 tie-in progressing? It's been over two months since I have seen this in day light, would be interested to know what the tie is like at the moment.

Its looking really well, the main part of the bridge is done and they're building the ramp to it at the mo, they're using the grey honeycomb stuff for the walls of the ramp (like the Kinsale Road Roundabout flyover) and thats just starting to take shape now.

I drive the road about every 2-3 weeks (from Cork, living in Galway) and its been pretty cool to see the progress of the bridge as the weeks go by! The way the bits fitted together was impressive considering the scale and weight of each part.

Sorry about my non technical language-I don't know much about roads etc but as I drive the route so often I'm interested as to how the project is doing (and the Crusheen Gort road too). The tunnel will seriously save so much journey time (and frustration of sitting in traffic). I'm amazed it wasn't built years ago!

Going a bit off topic but anyone else notice that on the road outside Limerick (I think its on the M20 not sure tho) there's a sign for galway that says 104km and then after you cross the river after all the roundabouts and Dock Rd chaos, there's a sign that says 105km to Galway! Either its a mistake in the sign or you actually travel a km or two thru Limerick and end up further away from Galway all bcos there's only one place to cross the stupid river! :eek:

mysterious

The Tralee/Kilarney road should be a third tier flyover going straight over the M7 to hit the mainline from the left.

KevR

brainyneuron wrote: »

Going a bit off topic but anyone else notice that on the road outside Limerick (I think its on the M20 not sure tho) there's a sign for galway that says 104km and then after you cross the river after all the roundabouts and Dock Rd chaos, there's a sign that says 105km to Galway! Either its a mistake in the sign or you actually travel a km or two thru Limerick and end up further away from Galway all bcos there's only one place to cross the stupid river! :eek:

There was a similar situation on the old N6 near Loughrea heading towards Galway. Just before Loughrea there was a sign saying Galway 38km and a minute later on the Loughrea Bypass there was a sign saying Galway 39km. Before the Loughrea Bypass opened it was only 38km as you were going straight through the town (but stuck in traffic); after the bypass was built you were going around the town, a more indirect route (but faster). They forgot to update the old sign to the East of the town when the opened the Bypass to reflect the new distance.

Could it be that the opening of a new road in Limerick is responsible for the distance abnormalities? I'm not very familiar with Limerick so I'm not sure. Maybe the sign on the M20 is showing the distance to Galway for traffic going through the Limerick tunnel? I know the tunnel isn't open yet but maybe they were just pre-empting it with the signs on the M20; it saves them having to update it when the tunnel opens.

bacon&cabbage

Ok I made a little movie of the Rossbrien interchange

I think all the annotations are correct, but I'm open to correction

Apologies for: The quality, My dirty windscreen and Michael O Leary having a rant at 2:45ish I forgot the radio was still on !

I've also got a screen grab from openstreetmap showing where the annotations are, in case someone is lost ! (8 and 11 are my own edits)

The Video
http://www.youtube.com/watch?v=PjvmsjiBOyM


Map

Chris_5339762

Nice one

I love the temporary "Limerick City Center" gantry

mysterious

Chris_5339762 wrote: »

Nice one

I love the temporary "Limerick City Center" gantry

City centre. Could you please not use American english! I can't stand when Irish people do it.

But on topic, those loops are so fecking tight...:rolleyes:

Chris_5339762

mysterious wrote: »

City centre. Could ypu please not use American english! I can't stand when Irish people do it.

I caught you before you had a chance to edit

Tech3

That was brilliant. Pretty much sums up the Rossbrien interchange.

The loops are not that bad. I spotted a few lads on a horse using the N7 east ramp from the M20 a few days ago. Shocking.

mysterious

Chris_5339762 wrote: »

I caught you before you had a chance to edit

You probably wrote in the quote, because it was an instant blunder. Your spelling error was intentional :P

Irish and Proud

mysterious wrote: »

City centre. Could you please not use American english! I can't stand when Irish people do it.

But on topic, those loops are so fecking tight...:rolleyes:

...yeah, that interchange is way underspec for connecting two motorways or HQDCs - the M50 interchanges (with limited space) would seem to be of a far higher spec. Referring to the video:

1) Agreed mate - that loop seems far to tight - should be like the one for the M2 Ashbourne South. The merge is also far too short - the engineers may have to consider dropping a lane on the M7 eastbound so as to have a lane gain for that loop, as well as a dedicated lane from the tunnel to the M20 South/City. Otherwise, there may be a few serious accidents at the loop's exit!

2) There seems to be no proper filter lane on the M7 westbound for the M20 south - just a tapered off-slip. That ramp should also be longer - FFS it's a motorway to motorway connection!

3) The M20 North to N7 Tunnel ramp seems to veer off a little abruptly. Also, the merge (though not dire) does not seem over generous.

This junction is not as per the original design - both loops seemed larger, and the south facing direct left connections seemed longer. Looks like a few corners were cut - literally! :rolleyes:

Dublin had limited space for its freeflow junctions and although the loops are tight there, at least there are decent merge lengths and mostly good long ramps (though undulating)! There is no such excuses for Rossbrien, especially when the original EIS design seemed superior - maybe they should bring in the Meath NRDO (very fond of long ramps and loops) to sort it out! :mad:

Regards!

Tech3

I reckon the AADT will rocket on the M20 at J1 to J3 as much of the current traffic uses J3. The M20 should really be D3M to J2 as it's going to be badly jammed with N7 east, traffic from the childers road outbound and the M7 west. That leaves an already bad situation worse for traffic trying to leave at
J2.

sonyair

should of built this instead:

mysterious

sonyair wrote: »

should of built this instead:

Thats worse.

Are you mad?