M7 - Naas/Newbridge Bypass Upgrade [Junction 9a now open]

Mantis Toboggan

I'd imagine the M7 will revert back to 120 and the N7 will be 100km.

Darc19

r3nu4l wrote: »

Does anyone know what the final speed limit will be on the M7 when this work finishes? Will it be 120kph (as it should be) or 100kph like the M50?

It will be 120 kph

The m50 is a different case. From airport to knocklyon there are simply too many junctions, so a limit of 120 was deemed unsafe.

Knocklyon to sandyford has topography issues which means 120 is unsafe for many vehicles. (speed limit has to take into account many vehicle types)

From sandyford to shankill, limit is 120.

There is a detailed report on this somewhere and probably accessible by a Google search.

kravmaga

https://www.irishtimes.com/news/ireland/irish-news/three-lane-section-of-m7-to-open-on-monday-1.3927611

marno21

kravmaga wrote: »

https://www.irishtimes.com/news/ireland/irish-news/three-lane-section-of-m7-to-open-on-monday-1.3927611

The Sallins bypass bridge under the main Dublin-Cork railway line will be constructed by Irish Rail under a separate but parallel contract.

Good up to date reporting right there.

OldMrBrennan83

Anyone been on it yet?


https://twitter.com/beat102103/status/1140525066922450944

Cazale

OldMrBrennan83 wrote:

Anyone been on it yet?

Drove in this morning at approx 7:30. The speed signs all still say 60km/h. Ended up being 15 minutes early for work which is a first!

OldMrBrennan83

Probably no harm in leaving it low for a little while until people get used to it.

ZX7R

Traffic seemed to be moving a log more freely no tail backs like every other morning

pad199207

Was on it this morning. Traffic was moving freely. The enforced speed limit seemed weird with the 3 lanes in place.

Pablod

Was on it around 7:00 this morning,
Flowing much better - majority of traffic stuck to lanes 2 & 3

obviously hard to gauge impact it will have at the moment until full stretch is 3 lanes and when schools are fully open etc.

But its a good start!

WishUWereHere

WishUWereHere wrote: »

Why would You think an 80kph is vital? Especially going SB, surely when the project is complete it ought to be 120kph?

On an aside, I still forsee speed restrictions being enforced ( J9A ) around KG while the bridge is being worked on.

I am not being very scientific here but basically because everyone is moving faster northbound, they are going to get to the m50 quicker and traffic will back up via the accordion effect (https://en.wikipedia.org/wiki/Accordion_effect) and I think it will heavily negate the benefits of the new lane. If we limit the traffic's progress with slower speed limitss everyone will get where they are going quicker.


This morning (17 of June):

that was a really nice surprise this morning, I didn't know they were opening three lanes.

I have been reading up since and the following quote on the Kildare County Council website concerns me (http://kildare.ie/CountyCouncil/PressReleasesAdverts/M7NaasNewbridgeBy-PassUpgrade-NotificationofTrafficManagementWorks.html):

"It is anticipated that, on week commencing the 24 June 2019, 3 lanes will be available Westbound from Junction 8 (Johnstown), to Junction 10 (Naas South). At that time the temporary speed limit will be increased on both the Eastbound and Westbound carriageways to 80kph between Junction 8 (Johnstown), to Junction 10 (Naas South)."

Surely this is going to be a disaster with three lanes merge into two and with everyone travelling 20 kilometres faster (and that's just the law abiding drivers), traffic could be worse heading southbound.

Anyways, fantastic progress today and the weather isn't bad either.

Pablod

Deleted User wrote: »

I am not being very scientific here but basically because everyone is moving faster, they are going to get to the m50 quicker and traffic will back up via the accordion effect (https://en.wikipedia.org/wiki/Accordion_effect) and I think it will heavily negate the benefits of the new lane.

Yes that's one of the main things that will be expected from this - traffic hitting M50 quicker/earlier with the "accordian effect" further back the N7.
The main benefit of this will be Outbound at peak times (West for the Compass folk)

Joey Joe-Joe Jr

Might there be a case for variable speed limits, slower at peak times?

Be well and win

Not everyone on it is heading for the M50 so for those of us who can come off at City west it'll be good. Surprised not to see speed cameras on it this morning, maybe they'll wait a couple of days and then catch loads

Be well and win

Be well and win wrote: »

Not everyone on it is heading for the M50 so for those of us who can come off at City west it'll be good. Surprised not to see speed cameras on it this morning, maybe they'll wait a couple of days and then catch loads

I have seen the accordion effect in action and I get off at Citywest too. This only happens though at peak times off the year at peak times of the day and it can go out as far as junction 7 in my experience.

Edit: Variable speed limits would be amazing technology to see in place.

Sam Russell

Be well and win wrote: »

Not everyone on it is heading for the M50 so for those of us who can come off at City west it'll be good. Surprised not to see speed cameras on it this morning, maybe they'll wait a couple of days and then catch loads

The opening was said to be next week so it might be the Gardai were told it will not open till next week. Expect a few speed checks next week.

harr

On it this morning for a few miles, 60 seems very slow and not many sticking to it. Took 10-15 minutes off my usual time today so happy out with that and that was me driving just over the 60.

MaceFace

I don't see how a slower speed limit will really help as in most cases during rush hour, people are attempting to get to a particular destination (work) for a particular time so the departure time will change depending on conditions.

Doesn't the accordion effect occurs when there is a reduction in traffic speed and then an increase? We see it every day heading south bound at the "Rathcoole hill". Traffic tends to slow as it moves up the hill tricking back down causing people to brake, and then clear back out on the way back down towards the Applegreen.

At a 120kph speed, it happens a lot with cars pulling in front of faster oncoming traffic causing those behind to brake.

We see it also at the current work zones either with cars joining the mainline or changing of lanes even with the 60kph limit.

I think the faster limit will allow the many people coming from Naas South and beyond who leave earlier and just before the morning rush to get through the red cow interchange before the rush hour traffic snarls it all up as they are getting there quicker.

_Kaiser_

Passed through this morning around quarter to 9.

Free flowing for a change with no stops beyond at the Carlow merge. Trucks and some cars using lane 1, most cars in lane 2 and 3 and easily capable of doing 60+. From what I can see, this stretch to exit 9 could easily be 80 or 100 right now.

OldMrBrennan83

Sam Russell wrote: »

The opening was said to be next week so it might be the Gardai were told it will not open till next week. Expect a few speed checks next week.

Would 100% need average cameras for that. Can't understand why they weren't installed as part of the upgrade.

wheres me jumpa

I haven't stopped smiling since finishing my commute this morning!

Left at a typically bad time, particularly for a Monday and still made it with 10-15 mins off my regular.

marno21

VSLs from J11 to the M50 should have been mandated as part of this upgrade

Hopefully they will follow when the M50 upgrade is complete

At the very least they should be included on the proposed M3, M4 and M11 upgrades forthcoming

_Kaiser_

OldMrBrennan83 wrote: »

Would 100% need average cameras for that. Can't understand why they weren't installed as part of the upgrade.

No thanks. There's too much of an obsession with "speeding" as it is that it's used as a means to avoid dealing with anything else.

KBurke85

Great to see 3 lanes open but I think secondary schools being off and state exams practically over had a bearing on the lack of traffic a bit this morning also

Darc19

Sam Russell wrote: »

The opening was said to be next week so it might be the Gardai were told it will not open till next week. Expect a few speed checks next week.

I think the reason is that the official speed restrictions apply to both carriageways and you can't change one carriageway without changing the other. Hence the change next week.

It should make a difference to all dublin bound traffic, but not a big difference. The delay around Naas and Newbridge will be gone, but same number of vehicles as current will be looking to go through newlands.

riddlinrussell

_Kaiser_ wrote: »

No thanks. There's too much of an obsession with "speeding" as it is that it's used as a means to avoid dealing with anything else.

I think in general there's an issue of over focusing on 'speeding', especially in regard of safety in places where the current road design is the greater threat. But these main trunk roads are one place where I'd agree with VSLs enforced by automated cameras. Purely from a traffic management perspective, it's hard for the human brain to really connect that "less speed means we get there faster" for certain cases

SoupyNorman

wheres me jumpa wrote: »

I haven't stopped smiling since finishing my commute this morning!

Left at a typically bad time, particularly for a Monday and still made it with 10-15 mins off my regular.

More of this please.

I felt the same when I got past J10, it was an amazing feeling after spending what felt like an eternity wedged between two barriers.

My normal door to door is usually 55mins, was 47 this morning. So many extra minutes for activities.

Sam Russell

riddlinrussell wrote: »

I think in general there's an issue of over focusing on 'speeding', especially in regard of safety in places where the current road design is the greater threat. But these main trunk roads are one place where I'd agree with VSLs enforced by automated cameras. Purely from a traffic management perspective, it's hard for the human brain to really connect that "less speed means we get there faster" for certain cases

There has been research in the USA on this and they found that the greatest throughput of cars occurred at a speed of about 43 kph (27 mph) as cars closed up as the speed reduced, but not much below that speed.

Average speed limits enforced by cameras gets all traffic travelling at the posted speed. This improves throughput and reduces accidents, and would get all three lanes used.

They should have at least put up the gantries.

wheres me jumpa

SoupyNorman wrote: »

So many extra minutes for activities.

I just sat quietly in my car for the minutes I saved. It may take years of rehabilitation for me to adjust.

OldMrBrennan83

_Kaiser_ wrote: »

No thanks. There's too much of an obsession with "speeding" as it is that it's used as a means to avoid dealing with anything else.

As this isn't the place to argue the merits of speeding, we can agree to differ on that point.

I just mean if people agree that variable limits are the solution to greater throughput then there's absolutely no point in implementing them without an actual way to regulate the speed. Average cameras are the only way.