NRA to scrap 2+1 roads or not?

spacetweek

There is an international perspective on 2+1 here: Skyscraper City
It's kinda sad that 2+1s don't seem to work in Ireland. They're a road type that require discipline and dare I say it this discipline is probably forthcoming in better organised countries like Sweden and Germany, but not here.

MLM wrote:

It looks like the NRA is going to do away with the HQDC. The 2+2 sounds similar to a British dual carriageway. They are also trying to enact legislation to upgrade most of he existing HQDC's to motorway.

It doesn't look like that at all. The 2+2s are replacing 2+1s, not HQDCs. Presumably all HQDCs will still go ahead as-is - the article doesn't say anything about HQDCs.

Chris_533976 wrote:

I dont like how they're calling them 2+2s though. Does that effectively mean at-grade DC with median crossings???? Or full DC?? Need more infos

Since 2+1s have at-grade crossings (usually roundabouts), yes, 2+2s will be at-grade DC. Since they're only programmed for national secondaries and the quieter primaries, they're probably appropriate. Remember that such roads currently are at-grade AND have only 1 lane in each direction, so this represents a major upgrade.

MLM

spacetweek wrote:

It doesn't look like that at all. The 2+2s are replacing 2+1s, not HQDCs. Presumably all HQDCs will still go ahead as-is - the article doesn't say anything about HQDCs.

Yes but the NRA have been trying to get legislation through to allow them to upgrade the majority of HQDC's to motorway standard. Most of the Inter-Urbans will probably be Motorway by 2010. Believe it or not there is more than one article on the subject. Have look at this thread - http://www.boards.ie/vbulletin/showthread.php?t=2055114019&referrerid=&highlight=NRA

unkel

I like 2+1 and its safer overtaking compared to 1+1. But if it only costs 10-15% more to go 2+2, then that's surely the most efficient investment for minor national roads?

parsi

What I find with the Cork - Mallow one is that the folk who go at around the 70-80 mark suddenly speed up when they see a nice 2-lane road so you've sweet all chance to overtake. Of course they then slow back down when they go back to the 1-laner.

road_high

Bards wrote:

corktina wrote:

please see

http://www.farmersjournal.ie/2001/1215/journal_2/index.html - from 2001

http://www.transport.ie/viewitem.asp?id=5535&lang=ENG&loc=1714 - from 2004

http://www.munster-express.ie/060113/news1.html - from Jan 2006

and finally

http://www.waterford-today.ie/index.php?id=18950&what=1&issue=311 - July 2006
(8 fatalities since it opened)


after reading these reports, do you still hold the view thta becuase it is a light trafficed road (your opinion) that this is not needed

If memory serves me correct there were something like 6 fatal collisions on this road within a couple of years of opening. Something drastic was needed and 2+1 was a good option in my opinion. To my knowledge there have been no fatalities since it was fin last summer on he N24 Piltown bypass. So it must be working. Even though locals were out out by junction changes.

icdg

MLM wrote:

The 2+2 sounds similar to a British dual carriageway.

2+2 is a dual carrigeway. A rather low quality, at grade-junctions one by the sounds of it, but its' still a dual carrigeway if there is anything in the way of central median.

(Without the central median its S4, four lane single carriageway which is a different thing of which there are precious rare examples, there's a strech on the outskirts of Galway city but that's the only one I can think of the country).

murphaph

icdg wrote:

2+2 is a dual carrigeway. A rather low quality, at grade-junctions one by the sounds of it, but its' still a dual carrigeway if there is anything in the way of central median.

(Without the central median its S4, four lane single carriageway which is a different thing of which there are precious rare examples, there's a strech on the outskirts of Galway city but that's the only one I can think of the country).

S4 near swords too.

Yeah, it's D2. It's very high standard for the roads we're talikin about and would probably never be used on roads in the UK with such low traffic levels. They'd remain S2.

Bards

mfitzy wrote:

If memory serves me correct there were something like 6 fatal collisions on this road within a couple of years of opening. Something drastic was needed and 2+1 was a good option in my opinion. To my knowledge there have been no fatalities since it was fin last summer on he N24 Piltown bypass. So it must be working. Even though locals were out out by junction changes.

8 fatalities since it opened.... But my point exactly. these are the type of roads where 2+1 saves lives. it doesn't matter a damn if they are lightly trafficked or not, it's all about engineering roads to a safer standard to protect all road users

for example Naas Dual Carriageway was probably built at a time when there was less cars on it than the present N24

dowlingm

In fairness, Cork-Mallow was designed before 2+1 came into vogue with the media. The design flaw was that where 1 became 2 the traffic flow was into the fast lane, not the slow lane, thus requiring people to move left, something Irish drivers refuse to do. If the single lane became the slow lane it would take a deliberate lane change for the slow drivers to bog down everyone else.

jlang

I'm amused that they've decided to abandon the 2+1 experiment before the original pilot schemes are even operational. The N2 Castleblaney[SIZE=-1]/Clontibret [/SIZE]by-pass (to open soon enough) is a new build 15km road that would have given the design a better evaluation than the retro-fitted Mallow road which is/will be busy enough that it should be dual carriageway anyway.

Although I do agree with the NRA that for green field schemes the extra land take for a continuous fourth lane is probably worth the extra cost, even if the traffic numbers will never justify it. And because of generations of poor planning, a large amount of the new regional N roads will need to be through green fields parallel to the old ones.

Skyhater

jlang wrote:

I'm amused that they've decided to abandon the 2+1 experiment before the original pilot schemes are even operational. The N2 Castleblaney[SIZE=-1]/Clontibret [/SIZE]by-pass (to open soon enough) is a new build 15km road that would have given the design a better evaluation than the retro-fitted Mallow road which is/will be busy enough that it should be dual carriageway anyway.

Although I do agree with the NRA that for green field schemes the extra land take for a continuous fourth lane is probably worth the extra cost, even if the traffic numbers will never justify it. And because of generations of poor planning, a large amount of the new regional N roads will need to be through green fields parallel to the old ones.

I could never understand why the NRA decided to use the Castleblayney bypass as a 2+1 trial.
This was a brand new road, 2+1's are designed for retrofitting old roads.
The N2 is probably one of the busiest non DC primary roads, and something could have been learned if the C'Blayney bypass was made into a 2+2 road.

Also, I don't understand why they decided to put a couple of roundabouts on the road instead of grade separated junctions (like they did on the Carrickmacross by-pass, and some of the C'Blayney by-pass junctions).
The main Castleblayney junction definitely should have been grade-separated.

RadioCity

Travelling south from Monaghan, it looks to be a free flow onto the new road with a small roundabout (almost immediately) on the R184 for Ballybay and probably Clontibret.

South of 'Blayney is what is a pathetically small roundabout for the volume of traffic going to be using it. Even if grade separation wasn't happening, a lane to "bypass" the roundabout for northbound traffic would have saved the need to stop. The roundabout is effectively a traffic calming device as you will have to virtually stop at it. Word is that its due to open next month according to local rumour.

Slightly off topic but the rounabout on the south end of the Monaghan bypass looks as if its being resized to allow 2 lanes on it. Up til Tuesday it had 2 lanes on the northbound approach, not that 2 cars could even use it together. There is only one lane now. Well for the time being.

ich_verschwinde

There's nothing wrong with these 2+1 roads in my opinion.. if every N road in the country was a 2+1 then it wouldn't be that bad. if their a cheap alternative then why not? some N roads badly need upgrading, asap.. and if a 2+1 would save time then why not?
i hear they're planning a 2+1 for the N20 Buttevant, Clarleville Bypass .. (ages away yet) .. noone would complain about that.. better than been stuck behind a tractor at 10km/h and no chance of overtaking.. which often happens on this road

Chris_533976

I would complain, I thought Cork - Limerick was planned to be full grade separated dual carriageway? Where did you hear otherwise??

MLM

ich_verschwinde wrote:

There's nothing wrong with these 2+1 roads in my opinion.. if every N road in the country was a 2+1 then it wouldn't be that bad. if their a cheap alternative then why not? some N roads badly need upgrading, asap.. and if a 2+1 would save time then why not?
i hear they're planning a 2+1 for the N20 Buttevant, Clarleville Bypass .. (ages away yet) .. noone would complain about that.. better than been stuck behind a tractor at 10km/h and no chance of overtaking.. which often happens on this road

The NRA has had this stretch of road in planning for ages as a DC. 2+1 would not be suitable. It's too heavily trafficed.

Chris_533976

I do hope tho that it gets FULL dc and not this at-grade 2+2.

MLM

What with the NRA trying to bring in new legislation, it might even end up as motorway. Traffic levels certainly justify it. http://www.nra.ie/Transportation/TrafficDataCollection/TrafficCounterData/

po0k

Capt'n Midnight wrote:

They can't be more dangerous than a national primary route reduced to 70kph by some dithery driver who slows down further on bad bends and continues at 70kph through resedential areas so you can't pass then safely or legally.

They should be pulled over and shot.

Niall1234

I have one problem with 2+1.

Imagine the scenario of very very heavy traffic coming back from a match.

It would be fine when it is one lane. When it switches to two lanes, both lanes would fill up. This would then result in a massive backlog at every single point where the road goes from 2 to one lane. Essentially every few miles.

Could you imagine the traffic chaos this would cause ?

bk

ich_verschwinde wrote:

There's nothing wrong with these 2+1 roads in my opinion.. if every N road in the country was a 2+1 then it wouldn't be that bad. if their a cheap alternative then why not? some N roads badly need upgrading, asap.. and if a 2+1 would save time then why not?

Well if DC costs only 10% more then 2+1, then I'd say why not?

It looks like the old Irish mind set of penny pinching to save on just 10% now, when the 2+1's would all probably need to be upgraded later due to increasing traffic volumes and would probably cost far more then if they just went DC from the start.

Just look at the 2+1 in cork or the M50 for examples of short sighted penny pinching that costs more in the long term.

I'm glad that the NRA are starting to take the long view and building roads speced for the future, not today (see Motorways where DC's would currently do and now DC's instead of 2+1).

MrPudding

They seem to work in other countires. I always thought the purpose of them was not so much to increase the capacity of the roads but to allow faster traffic regular and safe oportunities to pass slowing moving traffic.

MrP

ich_verschwinde

ya, sorry my bad... the plans for Buttevant, Charleville is for a DC.. but omg is it needed. I unfortunately have to travel that road alot. But stretch 5km either side of buttevant is just a disgrace. like the road running outside my house (an unclassified country road) is actually wider and smoother..
its going to be another 5-8 years before anything is complete i'd say..

The 2+1 roads in Sweden are being built as Autostrasse .. they seem to be working there
but i find the ones on the mallow road.. 1km of overtaking lane just doesnt give enough time for all faster traffic to disperse.. 5 km each way would be way more suitable i think. but this is only "experimental" i guess..

Chris_533976

Niall1234 wrote:

I have one problem with 2+1.

Imagine the scenario of very very heavy traffic coming back from a match.

It would be fine when it is one lane. When it switches to two lanes, both lanes would fill up. This would then result in a massive backlog at every single point where the road goes from 2 to one lane. Essentially every few miles.

Could you imagine the traffic chaos this would cause ?

N20 2+1 every morning at rush hour Chaos. Whole thing grinds to a halt.

Zoney

Chris_533976 wrote:

N20 2+1 every morning at rush hour Chaos. Whole thing grinds to a halt.

Not even just at rush-hour. The route gets worse every time I've been down it - each of the towns along the way are becoming far more serious bottlenecks than in the past. It's really irritating the lack of progress on the N20 - by rights the Dublin interurbans should be done and dusted by now with work well underway on the N18 and commencing shortly on the N20, N24, N15, N2, etc.

Chris_533976

Blarney - Mallow is alright at the moment, bar the 2+1 jams. Although I'd love to see it as full DC, most of it is wide S2 with passing lanes and there arent really any bottlenecks.

Mallow - Croom is awful though, truely awful.

I said it on Sabre I think, cant remember.... but if they took the money they're putting into the Mitchelstown - Fermoy section of the N8, where there are no bottlenecks, and ploughed that cash into to the Mallow - Croom section (bypass the disasters that are Buttevant and Charleville) then it would all be better.

I really cant understand the Atlantic Corridor thing. They make a HUGE fuss about it, then make a huge fuss about the N18, but yet the N20 is forgotten. I dont get it.

MLM

Chris_533976 wrote:

I really cant understand the Atlantic Corridor thing. They make a HUGE fuss about it, then make a huge fuss about the N18, but yet the N20 is forgotten. I dont get it.

It must be a politics thing. The traffic levels on the non DC part of the N20 are higher than the non DC part of the N18. Though Cork co co have started to plan for the eventual upgrade of the entire N20 to DC, possibly motorway

Chris_533976

Then you see something likethis

http://www.e-tenders.gov.ie/search/search_show.aspx?ID=JUL088971