N20 Mallow to Rathduff Pilot 2+1 Scheme

marno21

The N20 2+1 pilot scheme installed in ~2006 seems to be regarded by the NRA as a failure as there is currently major roadworks ongoing on this stretch of road concerning the removal of the wire barrier seperating the 'carriageways'.

Whilst I knew this would happen one day, I always assumed this would happen when the M20 was being built beside it and this was becoming the alternative route. 2+1 has its pros and cons but it's best suited to lower traffic routes with infrequent junctions to provide overtaking opportunities, not a road with a very high AADT and lots of junctions meaning lots of 1+1 stretches.

(Said I'd keep this out of the M20 thread as that should be used for discussing the actual M20, and the regular debate about whether it should shadow the N20 or not which some people won't drop)

L1011

I believe it ended up having a noticeably higher accident rate than a non divided carriageway did, as did the N24 Piltown 2+1.

The NRAs 2+1 implementations were all incredibly poor and it could definitely have its place in certain areas, if done right - but on new or retrofit to very new build roads only, as frequent junctions and gaps in the barrier kill the concept.

Jayuu

L1011 wrote: »

I believe it ended up having a noticeably higher accident rate than a non divided carriageway did, as did the N24 Piltown 2+1.

The NRAs 2+1 implementations were all incredibly poor and it could definitely have its place in certain areas, if done right - but on new or retrofit to very new build roads only, as frequent junctions and gaps in the barrier kill the concept.

I really think the poor implementation of the 2+1 pilot schemes was a huge loss from a development perspective. There are numerous schemes that could be done as 2+1 where the volumes don't justify full 2+2 or HQDC standard. And proper 2+1 would be better than WS2 in practically all circumstances.

But the N24 Piltown 2+1 is a complete disaster especially driving it at nighttime (which thankfully I haven't had to do for a few years now).

road_high

I think they are fantastic, providing regular safe overtaking opportunities. It's just the woeful standard of Irish driving made them not work to their optimum.

AugustusMinimus

road_high wrote: »

I think they are fantastic, providing regular safe overtaking opportunities. It's just the woeful standard of Irish driving made them not work to their optimum.

They aren't designed to cope with the levels of traffic on the Mallow road. A lot of people for some ungodly reason seem to drop to 80 or even 70kph on the single section on the Mallow road whereas they do the full 100kph the second you go to overtake them.

AugustusMinimus

L1011 wrote: »

I believe it ended up having a noticeably higher accident rate than a non divided carriageway did, as did the N24 Piltown 2+1.

The NRAs 2+1 implementations were all incredibly poor and it could definitely have its place in certain areas, if done right - but on new or retrofit to very new build roads only, as frequent junctions and gaps in the barrier kill the concept.

I don't think we'll see them again. The difference in price with 2+2 just doesn't justify 2+1.

Leonard Hofstadter

Indeed, 2+2 is hardly any more expensive but is much safer because there's no need to speed past slowcoaches on the 2 lane bits for fear of being stuck behind them for another 2 km. It also means even on the less busy roads you'll never get held up by a slow driver, so it's quicker and much safer for hardly any extra money. Hopefully this will be the standard for any future N road that does not justify a HQDC or motorway.

Jayuu

AugustusMinimus wrote: »

I don't think we'll see them again. The difference in price with 2+2 just doesn't justify 2+1.

My worry is that instead of 2+2 we'll get WS2 on certain roads instead. 2+1 could have been a handy compromise.

Markcheese

AugustusMinimus wrote: »

I don't think we'll see them again. The difference in price with 2+2 just doesn't justify 2+1.

Could you put a dual carraigeway (2+2) on that stretch of the mallow road??

AugustusMinimus

Markcheese wrote: »

Could you put a dual carraigeway (2+2) on that stretch of the mallow road??

I doubt it would cost that much. However, there would be loads of at grade junctions. We don't build dual carriageway in this country with at grade junctions anymore.

Chris_5339762

Jayuu wrote: »

My worry is that instead of 2+2 we'll get WS2 on certain roads instead. 2+1 could have been a handy compromise.

WS2 isn't being built anymore. For any upgrades you'll either get decent S2, or 2+2 (Type 2). (or of course HQDC/Motorway (Type 1 as its known))

TheBigGreen

So they are removing the wire barrier and putting in what? I travel it everyday and saw a good few crashes in the last 3/4 months.

Carawaystick

AugustusMinimus wrote: »

I doubt it would cost that much. However, there would be loads of at grade junctions. We don't build dual carriageway in this country with at grade junctions anymore.

The R132 at Dublin airport was built with at grade junctions just 2 years ago

L1011

Carawaystick wrote: »

The R132 at Dublin airport was built with at grade junctions just 2 years ago

Not by the NRA.

Carawaystick

L1011 wrote: »

Not by the NRA.

Chris didn't qualify who built the roads.

AugustusMinimus

I should have qualified my comment. They don't build 2+2 with at grade junctions unless signalised or roundabout based.

Are their any unsignalised junctions on the R132 which would involve traffic crossing over 2 lanes of moving traffic in the other carriageway?

Carawaystick

Not on the new section.
It's 4 lanes wide, 2 general traffic, 1 bus. 1 bike&walking ( which is 3m wide)

TheBigGreen

They are starting to work on the N20 now! Are they widening the road? Seen them cutting down trees around 5/5.30 yesterday evening.

TheBigGreen

When are the works supposed to be finished?

marno21

TheBigGreen wrote: »

When are the works supposed to be finished?

December 18th but I'm open to correction on that

TheBigGreen

marno21 wrote: »

December 18th but I'm open to correction on that

Thanks for that.

Are they getting rid of all the wire barriers? The second 2+1 is still been used.

niloc1951

Just back from three months in Europe and never seen a cheese wire separation on 2+1 sections which are very common, particularly in France.

Also what is our preoccupation with having a hard shoulder.
I have driven thousands of kms. of road where there is no hard shoulder because where space permits it is used to provide 2+2 or 2+1 with emergency stopping places. On such sections which do not have a central divide just a continuous white line the speed limit is the same as ordinary roads.
I understand if a driver is caught on the wrong side of attracts a summons based on dangerous driving, which probably accounts for the fact that I have never seen anyone committing the offence.

There are 2+2 and 2+1 which do have ARMCO or a Jersey Wall separation where the speed limit is increased to 110kmh (dual carriageway limit) and these can be as short as 1km, but the increased limit permits faster/safer overtaking of slower vehicles.

The above solutions greatly increase road capacity and provide a less stressful and safer driving environment for minimal cost.

Markcheese

Its the frequent junctions on that stretch of road that cause problems... and yes I wonder about hard shoulders especially on n roads .
Are they moving down to do the next 2+1 stretch after christmas or is that it ...

TheBigGreen

Markcheese wrote: »

Its the frequent junctions on that stretch of road that cause problems... and yes I wonder about hard shoulders especially on n roads .
Are they moving down to do the next 2+1 stretch after christmas or is that it ...

That's what I'm wondering!

AugustusMinimus

Anyone have photos of the work done?

niloc1951

Markcheese wrote: »

Its the frequent junctions on that stretch of road that cause problems... and yes I wonder about hard shoulders especially on n roads .
Are they moving down to do the next 2+1 stretch after christmas or is that it ...

What's common in Europe is where there's a junction on an 2+2 or 2+1 the road reverts to 1+1 with the centre reserved for turning vehicles.

On such sections you may also see a layout which allows traffic emerging from a side road and turning left (right here) to execute the manoeuvre in two parts, first to a waiting lane in the middle of the road, usually a continuation of waiting lane for traffic turning left (right here) off the road, and than merging onto the through lane on the main road when there is a gap in the traffic. It means that vehicles emerging from the bye-road and turning left (right here) don't have to wait until traffic is clear from both directions.

D Trent

niloc1951 wrote: »

What's common in Europe is where there's a junction on an 2+2 or 2+1 the road reverts to 1+1 with the centre reserved for turning vehicles.

On such sections you may also see a layout which allows traffic emerging from a side road and turning left (right here) to execute the manoeuvre in two parts, first to a waiting lane in the middle of the road, usually a continuation of waiting lane for traffic turning left (right here) off the road, and than merging onto the through lane on the main road when there is a gap in the traffic. It means that vehicles emerging from the bye-road and turning left (right here) don't have to wait until traffic is clear from both directions.

If you've taken a trip to Belfast recently you'll have seen this as soon as you bypass Newry

marno21

Looks like I was wrong, they seem to be putting the posts back in for the wire barrier on the resurfaced section now

TheBigGreen

Is there more road works early in the new year?

Truckermal

TheBigGreen wrote: »

Is there more road works early in the new year?

Ya they are doing up to Rathduff I was surprised to see the wire up again..

marno21

It was just a resurfacing, barrier replacement and drainage addition scheme. I didn't notice anything wrong with the surface before, considering all the traffic chaos it caused over the last 4 months. Not sure if many here drove it at night but it's possibly the most difficult drive I ever did at night with the constant cones and steel barrier along with the narrow twisty lanes for the 4 months.

Vanquished

marno21 wrote: »

It was just a resurfacing, barrier replacement and drainage addition scheme. I didn't notice anything wrong with the surface before, considering all the traffic chaos it caused over the last 4 months. Not sure if many here drove it at night but it's possibly the most difficult drive I ever did at night with the constant cones and steel barrier along with the narrow twisty lanes for the 4 months.

There were a few depressions and the surface was degrading a little in spots but on the whole it was more than adequate. The main issue was a lack of reflectors on the wire barrier! The works were poorly timed when you consider the mess that is still ongoing just up the road in Buttevant. The disruption was painful at times and the works did appear to persist for an inordinate amount of time on what was a relatively short stretch. It looks like they are ready to move on to the next section in the new year too.

I'd agree with your views on driving through the works in the dark too. I found it quite disorientating at times especially in the rain. The never ending line of cones, varying lane widths and poorly signed junctions made for an uncomfortable drive. Many others made similar remarks to me as well.

Markcheese

The wire has been removed and barriers put up for another km or so towards rathduff -so assume they'll start on that in january..

TheBigGreen

Haven't seen notice of works to commence, will they put it off because of the damage to other roads in the county?

cjpm

This total waste of money is due to recommence in March. Expect traffic bedlam! The section they are still to do will be ripped out again if the M20 ever gets built.

Jayuu

cjpm wrote: »

This total waste of money is due to recommence in March. Expect traffic bedlam! The section they are still to do will be ripped out again if the M20 ever gets built.

Does that not tell you something about the probably timeline for the M20?

cjpm

Jayuu wrote: »

Does that not tell you something about the probably timeline for the M20?

Ha. It's not exactly uncommon for a lack of foresight in a government department resulting in a waste of tax payers money is it??

Jayuu

cjpm wrote: »

Ha. It's not exactly uncommon for a lack of foresight in a government department resulting in a waste of tax payers money is it??

I don't necessarily disagree with you. However in this case I think that, bar some radical change in policy, we aren't going to see the M20 started anytime before 2020. I hope I'm wrong on that though because I think it's a necessary piece of infrastructure.

niloc1951

I don't often use this road but last week I had reason to use it four times.
Driving south in the dark each evening I found it very difficult to keep to a proper line. The wire and posts were almost invisible and the ditch difficult to see.

The wire and newer jersey wall sections urgently need decent lane marking with reflectors.

Why the T.I.I. don't adopt the simpler and cheaper system of 2+1 using paint and rumble strips beats me.
Such a system is widely used in Europe where the speed limit is that of an ordinary road. 2+1 with a physical divide usually has dual carriageway speed limits.
For example France had 90Kph on 1+1 & 2+1 (without physical divide) national roads, 110Kph on 2+2 and 2+1 with a divide, much more sensible.

marno21

There's a works speed limit in place now between Mallow and Rathduff of 60km/h until the 1st of October.

The N20 works are really never ending, and the net gain is minimal for all the delays.

niloc1951

marno21 wrote: »

There's a works speed limit in place now between Mallow and Rathduff of 60km/h until the 1st of October.

The N20 works are really never ending, and the net gain is minimal for all the delays.

Just did a Google route plan, Kent Railway Station Cork to Colbert Railway Station Limerick by road.

Via - N20, 99 kms, 1h. 20 mins., without traffic hold-ups.

Via - M8 & R513, 108 kms, 1h. 26mins., without traffic hold-ups.

Google Route Planner

With all the delays and reduced speed limits on the N20 it seems to be a no-brainer to use the M8 route.

I had reason to commute the N20 for a week a little while back and it is one of the most frustrating routes I have driven in my 40 odd years of driving.

kevin7

niloc1951 wrote: »

Just did a Google route plan, Kent Railway Station Cork to Colbert Railway Station Limerick by road.

Via - N20, 99 kms, 1h. 20 mins., without traffic hold-ups.

Via - M8 & R513, 108 kms, 1h. 26mins., without traffic hold-ups.

Google Route Planner

If you flip the direction of that drive, both routes comes out at 1h22m! The reason is the awkward approach into Limerick City from the M20. You can drive directly out from Limerick City to join the M20 at its beginning, but that motorway junction does not allow traffic coming from Cork to exit.

There's not much difference in time in the two routes.

I much prefer the M8+R513 route. Stress free driving on both roads. The N20 is terrible.

marno21

This isn't long off taking a year now, to resurface 7/8km of roadway.

Zero net gain and thousands of collective hours wasted in traffic. If they were any bit smart they would have returned it to WS2 or even WS2 with climbing lanes.

They're after repainting the Rathduff-Blarney section but they've shortened the climbing lanes also, not too sure why

AugustusMinimus

marno21 wrote: »

This isn't long off taking a year now, to resurface 7/8km of roadway.

Zero net gain and thousands of collective hours wasted in traffic. If they were any bit smart they would have returned it to WS2 or even WS2 with climbing lanes.

They're after repainting the Rathduff-Blarney section but they've shortened the climbing lanes also, not too sure why

There seems to be a constant drive towards both shortening and removing climbing lanes. It's like the authorities are trying to make traffic worse for no reason.

TheBigGreen

Is it suppose to be finish in October?

niloc1951

AugustusMinimus wrote: »

There seems to be a constant drive towards both shortening and removing climbing lanes. It's like the authorities are trying to make traffic worse for no reason.

There also seems to be no policy or standard for how climbing/overtaking lanes merge.
Sometimes it's the climbing lane is directed to merge with the overtaking lane and other times the overtaking lane is directed to merge with the climbing lane.

The natural and safest is for the overtaking lane to merge thus allowing traffic in the climbing lane to have right of way and safely maintain its momentum.

Vanquished

The re-lining of the N20 from Blarney to Rathduff has been a pretty shambolic effort in general. Firstly they removed the centre line and hard shoulder markings along much of that stretch around Christmas 2015. The cats eyes were also so worn and non reflective that it left the road in a pretty dodgy state during the dark Winter months!

Now with the repainting finally complete the new climbing lanes end about 100 or 150 metres before the sign advises. They reduced the length of the climbing lanes yet didn't bother to update the signage accordingly!

Markcheese

Some where theres a very well payed consulting engineer who's making it up as he goes along..

FrStone

Vanquished wrote: »

The re-lining of the N20 from Blarney to Rathduff has been a pretty shambolic effort in general. Firstly they removed the centre line and hard shoulder markings along much of that stretch around Christmas 2015. The cats eyes were also so worn and non reflective that it left the road in a pretty dodgy state during the dark Winter months!

Now with the repainting finally complete the new climbing lanes end about 100 or 150 metres before the sign advises. They reduced the length of the climbing lanes yet didn't bother to update the signage accordingly!

Until recently the signage there used say slow lane ends 200m, yet when the markings were redone on the road it clearly showed the right hand lane ends. We are lucky they cleared that up, it used cause fierce confusion.

marno21

Works to continue for 4 more weeks as per C103

https://twitter.com/c103cork/status/763309203897389056

marno21

War over the newly painted climbing lanes on the N20 between Rathduff and Mallow:

http://www.irishexaminer.com/ireland/new-road-safety-markings-between-cork-and-mallow-are-extremely-dangerous-442324.html