M40 motorway redesignation and demand management system [works ongoing]

spacetweek wrote: »

Reclassification will not make the slightest bit of difference to:

- Massive levels of traffic on the road
- Underpowered junctions and Douglas flyover
- Lack of public transport
- Lack of alternative routes

So the point of it is....?

Safety, pure and simple.

I’m not going to do all of the math on this, but lets take account of basic queueing theory and irrational human behaviour while driving. Assume for arguments sake that the two lanes are moving along at 60kmph and 90kmph (in our dreams you might say) and calculate the throughput per hour. Along come Fergus the farmer drawing hay at 30kmph. So what’s his impact - 30kmph and 90kmph ? No, its far worse than that. Greta the granny in the silver Yaris who is comfortable occasionally doing 45kmph tightly grips the wheel and shifts lanes to overtake the tractor and trailer, and accelerates rapidly to 40kmph for the 6 or 7 minutes it takes her to anxiously overtake. So now we calculate the throughput based on the lanes moving at 30kmph and 40kmph. You’re probably down to a third of the standard throughput at this stage, if even. That’s bad enough, but it’s not actually my primary concern. The human reaction to sitautions like this is hugh frustration and anger resulting in all manner of risks being taken. Undertaking, overtaking, tailgaiting, unsignalled spontaneous and last second lane changes to slip into the safe zone between moving vehicles, etc etc etc. Anybody familiar with the N40 will be well familiar with this behaviour on a daily basis. And it is this which drives the need to reclassify the road. I don’t for a moment disagree with any of your bullet points, we all know that some or all of these need to be addressed. The problem is that the road is a moving traffic jam and reclassification is the only quick fix/sticking plaster to reduce the risk associated with a road that is operating so very far beyond its design capacity. All of the other improvements, as I have said in a number of posts, need to be done. The problem is that they will take years, at best. In the meantime some action must be taken to bring order to the chaos.

The figures that marno21 posted tonight are mind boggling. I’m fortunate, my circumstances now allow me to pick and choose the time of day I travel that road, and the times I avoid it like the plague. But I commuted along it at rush hour for a number of years and it Is little short of a miracle that there aren’t a lot more serious incidents. I firmly believe that there will be one, sooner rather than later.

Fergus the farmer is probably driving a 50 kph vehicle, so he's still gonna be there,
Its not beyond imagination to have an alternative cycle path along a good portion of the route, a lot of its already either there or in public ownership... Bishopstown to Douglas anyway...
It is daft to have no viable public transport from dunkettle to curraheen... And then give out about numbers using their cars...

Another way to think about the N40.... where would you drive if you decided not to use it anymore? Its incredibly difficult to avoid. For me to get to work in the mornings, I have to drive on the N40, go through Cork itself (much slower) or get the ferry (much, MUCH slower). Thats it, there is no other option.

Public transport would be a 10 minute drive to Cobh rail station, 25 minutes on the train, a 10 minute walk and another 30 minutes probably on the 208.

Its a 40-50 minute drive plus a 10 minute walk from the work carpark, at rush hour.

BikeRacer wrote: »

Anyone who's regularly driven the M50 and has been stuck behind rolling road blocks caused by tractors capable of 50 km/h and safety crews clearing crash after crash everyday, will tell you this 'safety' argument for reclassification is nonsense.
The same vehicles will be on the same overcapacity infrastructure while they'll now have less reaction time due to the increased speed limit.

It has been made quite clear that there will be no increase in the speed limit, it will remain as it is on the N40.
I trust as you are so knowledgeable on the M50 that you know the speed limit on that is also 100 kph.

There was also a tractor pootling eastbound at about 615pm causing a rolling roadblock and three lorries in a row tried to pass it at once which obviously worked really well and wasn't dangerous at all

Chris_5339762 wrote: »

There was also a tractor pootling eastbound at about 615pm causing a rolling roadblock and three lorries in a row tried to pass it at once which obviously worked really well and wasn't dangerous at all

Ideal time of day for a bit of N40 farming.

It will still be there after the new work is complete though....so....
I'm still sticking with my position that "the NTA need to do something a bit more intelligent than different colour signs".

L1011 wrote: »

Designed and using road diesel

Green diesel cannot be used for 50kph vehicles.

Is that an actual law ?

kub wrote: »

Is that an actual law ?

Yes. It's only allowed for low speed vehicles. Nothing to do with commercial use in this case

My idea is to leave the viaduct as it currently is for the mainline, take the left hand lane of the M28, and bring it across a separate viaduct next to the current one, adding it to the Douglas East merge and reline things so that a third lane goes across the Kinsale Road flyover, which is wide enough.

No N40 disruption to build it.

Also there was a five car rolling crash tonight eastbound on the flyover. Five cars had all gone into the back of each other. How thats even possible I don't know, but it held the traffic back from Dunkettle and ironically made the whole thing flow better.

Is it me or are they taking forever to install these? I do understand that there are traffic restrictions etc etc, but how long can it take to erect these?

Chris_5339762 wrote: »

“the newsletter”

Any chance you could share this ?

Reported on 96FM that a person stopped his car and got out to take a selfie of himself with the shopping centre the other day.

The guy should be give a driving ban. What an idiot.

hans aus dtschl wrote: »

They could yep and your idea makes perfect sense as a low-hanging-fruit project, but you may have to wait for the CEO of Cork City Council to resign first. Ann apparently doesn't believe in putting in protected cycleways because some people cycle on footpaths. This is the level of thinking you have to deal with when campaigning for this type of infrastructure.

On the N40, gridlock after another rush hour crash southbound yesterday morning. The biggest issue still seems to be people weaving and merging at high speed. Speed averaging cameras in conjunction with the demand management system might be a solution?

The weaving is caused by incredibly poor lane usage. I’ve seen people just powder along in the overtaking lane at 80kph. Causes chaos.

It's would have be a camera based system, lots of cameras on gantries, detecting people driving like dicks... Wether it's speeding, weaving, aggressive lane changing or using phones, and yes it'd cost...

Yup, all are up. I do think they missed a trick though... there is one east of Carrigtwohill I think, but there is absolutely no VMS between Cobh on the N25 on the approach to Dunkettle. The first you meet is near the N28 junction on the South Ring.

Should have been one just west of the Cobh junction.

cantalach wrote: »

What exactly will this new signage achieve? I’m really not understanding the cost-benefit analysis here. I’m talking here about the initial usage of the gantries, i.e. not possible future uses (traffic enforcement, etc.) that might never happen.

The system will tell people there’s a slow-down or accident ahead. Can they do anything about it? Not usually. A diversion of eastbound traffic along Well Road and Skehard Road would be useless because the latter is a car park every morning anyway. And if the accident is east of the Mahon exit then tunnel-bound traffic has no option but to grin and bear it anyway. For westbound traffic, the alternate routes are even worse.

An electronic information system serves a purpose in sprawling suburbanised areas in the US where there are a myriad of alternate freeways onto which one can divert. But when it comes to movement across the south side of Cork, the N40 is the only show in town.

The idea - which works in some countries - is that the gantry's posted speed is the legal speed at the time. You can prevent people rushing headlong into a jam by slowing them down further out, thus giving the jam time to clear.

Here, the project is a "titanic deckchair" of epic proportions. They won't solve any problems for the foreseeable future. I can think of a hundred local capital projects that would improve traffic but the NTA and TII won't advance them, yet this one got the go-ahead.

Hibernicis wrote: »

I understood that this was prioritised as part of the enabling works for the dunkettle interchange upgrade. Presumably to provide journey time estimates and assist with routing and lane management during the works. I suspect that the people whinging about it now are the same ones who would decry it’s absence were it not in place once the works commence

Not in my case. Its presence or absence when the Dunkettle work starts will matter not a jot to me because my daily commute doesn't involve any of the affected N roads. In fact, I try to walk whenever I can.

cantalach wrote: »

Not in my case. Its presence or absence when the Dunkettle work starts will matter not a jot to me because my daily commute doesn't involve any of the affected N roads. In fact, I try to walk whenever I can.

I would too, but sadly my home and my job are 32km apart and neither are movable. Nor is there a reasonable public transport option.

Chris_5339762 wrote: »

I may sketch it out someday, but I had a good look at Google today, and its perfectly possible to widen the Douglas Viaduct to 3 lanes each way for only a tiny bit of land take from the pitches nearby and by demolishing an electricity substation, as well as a small encroachment towards the fire damaged shopping center. So when the TII lads say it isn't possible to widen it, that is not true.

I’ve always believed that widening it wouldn’t be that all that difficult. As you say, some land acquisition, some demolition and some clever engineering/bridge building solutions. It might also be necessary to loose a slip road or two. But certainly nothing that hasn’t been tackled in many urban motorway projects around the world.

As a matter of interest, have you a reference for TII’s statement that it is impossible ? I’d like to understand their reasons for stating this so categorically.