M50 thread

Sam Russell

Bray Head wrote: »

It's counter-intuitive but the lower the speed limit, the more capacity a road can carry.

I read sometime ago that the Americans have found that 27 mph (43 kph) was the optimum speed for max throughput. Higher speed increases the space between vehicles, while slower speed does not.

If they put variable speed limits they need absolute monitoring and automatic enforcement. Otherwise the exercise is pointless. Average speed is the best system of enforcement.

Cantona's Collars

Alun wrote: »

Yes, it's crazy ... there's a whole 1.5km of sliproad between where the M11 joins to the Bray North exit for traffic to sort itself out into the right lane, more than enough if everyone planned ahead a little bit.

It's as if the people leaving the motorway didn't know where they were going until the last second.

Dravokivich

Bray Head wrote: »

It's counter-intuitive but the lower the speed limit, the more capacity a road can carry.

My experience of commuting on the M50, was that you get lower speeds at peak time anyway. Is it going to make a difference if the limit is reduced from 100, when the average speed during the period is substantially lower already?

Dravokivich

Dravokivich wrote: »

My experience of commuting on the M50, was that you get lower speeds at peak time anyway. Is it going to make a difference if the limit is reduced from 100, when the average speed during the period is substantially lower already?

The best thing variable speed limits can do is to stop vehicles flying into the back of congestion and braking sharply, causing more congestion.
Smoothing out the flow by preventing the Glug-glug effect caused by driving faster than the traffic ahead will help a lot.

Dravokivich

[Deleted User] wrote: »

The best thing variable speed limits can do is to stop vehicles flying into the back of congestion and braking sharply, causing more congestion.
Smoothing out the flow by preventing the Glug-glug effect caused by driving faster than the traffic ahead will help a lot.

That's more so a lack of attentiveness regarding the traffic ahead. I see that happening on the n7 and r136, where you've already got lower speed limits. I don't think they'll change a poor attitude to driving that we acknowledge is present.

Kermit.de.frog

L1011 wrote: »

And Sean O'Neill is American!

He does not rule out expansion He is just trying to ease you all in.

They can easily add an additional lane between the N4 and N7, N3 and N2, M1 and Ballymun. Plenty of space and no need to CPO. Inexpensive.

They could also build new individual flyovers at some junctions to enhance capacity at slips that are trouble spots. Again inexpensive.

One of the problems with the M50 upgrade was that the freeflow links were too short and tight.

Kermit.de.frog

https://twitter.com/CirtecCT/status/1063024512881569793

Translated

We're conducting tests #RARx on the #M50 Dublin!

These works, framed in the planning tasks of the M50 asphalt operation next year, constitute the first experience with our RARx tyre powder additive in Ireland

What's going on there? Are they planning to resurface the motorway?

Alkers

Kermit.de.frog wrote:

What's going on there? Are they planning to resurface the motorway?

It's already started, there are some new sections of pavement with no road markings at the moment

Kermit.de.frog

Elevated toll lanes with their own dedicated flyovers are the best solution to the M50 problem.

Works great in US. This would work on the M50. (from 1:42). Not only elevated but in trenches too!

https://www.youtube.com/watch?v=-y1kVbVt_Uk

Alkers

Kermit.de.frog wrote:

Works great in US. This would work on the M50. (from 1:42)

There's too many exits on the M50 and the existing exits are already constrained as it is without having to fit another set of onramps and off-ramps at each junction.

Spend the money on public transport

pad199207

Ah yes plenty of solutions for the M50, just no more room for anything to be done.

Maybe some cross city tunnel project might be something better to spend on.

The Dublin Tunnel should never have stopped at the port, it should have continued onto the south side and joined up with the N11.

Kermit.de.frog

It should have been 6 lanes each way minimum too. They could have built underground off/on ramps to the surface. Instead we got poxy 2 lanes each way.:rolleyes:

There is space within the footprint of the M50 for at least 2 more lanes each way. This space could be used for elevated lanes which would provide more lane space...

We would be better off getting to a point where people are close to their places of work, rather than trying to make people travel for the sake of it.

marno21

MOD:

This thread is used for ongoing discussion of M50 operations, including planned or proposed improvements (many of which are ongoing including the variable speed limits).

There are no proposals to widen the M50 to six lanes or create an elevated second deck. TII have repeatedly stated that there will be no widening or adding of significant capacity to the M50, from now on it's asset sweating.

In light of this, if anyone would like to start a thread on their M50 fantasies they are welcome to do so. Lets keep this thread for the real world M50.

JohnC.

https://www.independent.ie/irish-news/motorists-urged-to-stick-to-new-unenforceable-speed-limits-on-m50-38509138.html

TII pressing ahead with variable speed limits in the absence of legislation. They say they will be advisory until legislation and hope people comply.

punisher5112

If it were another tax they would have it in over night...

Them gantries are up since the 3rd lane was added....

Shocking how slow we are at all this....

Last Stop

We can blame Lord Ross for this one. Tried to slip in ludicrous sliding scale fines with what was a relatively simple piece of legislation and now its stuck in the system.
Delighted TII finally see sense and just getting on with it. Reckon it will have a big impact although the media advertising the lack of legality doesn’t help especially considering those dopey enough to sit in the middle lane wouldn’t have known that :rolleyes:
https://www.irishexaminer.com/breakingnews/ireland/brexit-puts-brakes-on-shane-rosss-proposed-increased-penalties-for-speeding-891397.html

blackwhite

JohnC. wrote: »

https://www.independent.ie/irish-news/motorists-urged-to-stick-to-new-unenforceable-speed-limits-on-m50-38509138.html

TII pressing ahead with variable speed limits in the absence of legislation. They say they will be advisory until legislation and hope people comply.

Surely they've learned from the M7 works what sort of levels of compliance to expect without enforcement :rolleyes:

Pete_Cavan

JohnC. wrote: »

https://www.independent.ie/irish-news/motorists-urged-to-stick-to-new-unenforceable-speed-limits-on-m50-38509138.html

TII pressing ahead with variable speed limits in the absence of legislation. They say they will be advisory until legislation and hope people comply.

Is the legislative change to allow for variable speed limits, average speed cameras or both to be implemented?

I mean, is there a chance that, once the legislation is sorted and variable speed limits are enforceable, will the only enforcement will be whenever there is a van or Garda with the hairdrier there? That would basically mean nothing changes. Or are variable speed limits and average speed cameras going to be implemented in tandem?

Last Stop

Pete_Cavan wrote: »

Is the legislative change to allow for variable speed limits, average speed cameras or both to be implemented?

I mean, is there a chance that, once the legislation is sorted and variable speed limits are enforceable, will the only enforcement will be whenever there is a van or Garda with the hairdrier there? That would basically mean nothing changes. Or are variable speed limits and average speed cameras going to be implemented in tandem?

We already have average speed cameras in the port tunnel?
The speed for average speed cameras is fixed as far as I am aware. So even in the port tunnel when the advertised limit is 60kmph, the camera is still checking at 80kmph. I don’t think this can be changed easily either.

I think your underestimating the impact that a speed van would have though. When they put them on the M7 the speeding dropped significantly. Thankfully when they do the M4 widening they will be able to enforce average speed cameras from the start.

Another key benefit of the variable speed limits will be the ability to close lanes in the event of an incident. This will make it safer, reduce queues and speed up response times.

blackwhite

AFAIK the Port Tunnel is covered by a specific piece of legislation to allow average cameras for that stretch only.

The technology is available to allow for average cameras that cover variable limits - just a case of getting the legislation lined up, and getting the investment to purchase the tech

plodder

JohnC. wrote: »

https://www.independent.ie/irish-news/motorists-urged-to-stick-to-new-unenforceable-speed-limits-on-m50-38509138.html

TII pressing ahead with variable speed limits in the absence of legislation. They say they will be advisory until legislation and hope people comply.

I think it's a crazy idea unless they make it very clear that the limits are advisory. It could cause legal issues possibly if/when they do make them "legal".

Also, the article doesn't say whether average speed measuring cameras will be in use (like the port tunnel). Without them, the whole measure will be useless, whether the limits are advisory or mandatory.

It should be fairly easy to know whether they're advisory or mandatory, the mandatory limits will have the red circle lit.

punisher5112

I honestly hope these are fitted between 1am and 5 am as any other time will cause crashes and other tools slowing down to gawk at them....

L1011

Don't advisory limits have to end in 5s as well as have a black circle rather than red? Or did I imagine that

plodder

L1011 wrote: »

Don't advisory limits have to end in 5s as well as have a black circle rather than red? Or did I imagine that

The traffic signs manual has a "Cautionary speed" plate with 25, 35, 45, 55 or 65km/h. I never noticed that before. It's interesting that they use speeds that are distinct from the statutory limits, and maybe that is done to avoid exactly this type of confusion.

Many countries have specific advisory speed limit signs (in Europe typically with a blue background) that would be easier to depict on overhead variable message signs. But, afaik we don't have them. Maybe the simplest thing is just to put something like "50km/h advised" in words, rather than a regular sign as such, or worse using actual speed limit signs out of the traffic manual, and pretend that they have the normal meaning. That would be very stupid.

Deleted User wrote: »

It should be fairly easy to know whether they're advisory or mandatory, the mandatory limits will have the red circle lit.

I see that is what they do in the UK. So, maybe that's what will happen.

Pete_Cavan

Last Stop wrote: »

I think your underestimating the impact that a speed van would have though. When they put them on the M7 the speeding dropped significantly. Thankfully when they do the M4 widening they will be able to enforce average speed cameras from the start.

I know speed vans have an impact, the problem with them is they are not there all the time and people usually speed, slow down when approaching the van (many have to anyway as cars in front often jam on the brakes when they see them, even if not exceeding the limit) and put the foot down once past the van. We need average speed cameras as a constant, permanent solution which will cut out a good bit of the crap that goes on on the M50.

veryangryman

Let's for a moment imagine that the m50 circle gets complete.

What will happen to the port tunnel toll. Will people stoll get screwed for a tenner if taking the clockwise route swords to bray?

blackwhite

veryangryman wrote: »

Let's for a moment imagine that the m50 circle gets complete.

What will happen to the port tunnel toll. Will people stoll get screwed for a tenner if taking the clockwise route swords to bray?

The intention of the Port Tunnel is to take trucks away from the city centre (and quays in particular). It was never intended for significant car or commuter traffic.

The €10 toll is deliberately targeting motorists at peak times to ensure that cars don’t cause congestion in the tunnel, leaving it free for HGVs and buses/coaches

Sam Russell

blackwhite wrote: »

The intention of the Port Tunnel is to take trucks away from the city centre (and quays in particular). It was never intended for significant car or commuter traffic.

The €10 toll is deliberately targeting motorists at peak times to ensure that cars don’t cause congestion in the tunnel, leaving it free for HGVs and buses/coaches

Does not seem to be working at the moment as AA Roadwatch on Morning Ireland said they were metering southbound traffic into the tunnel today because of congestion. I think that this can only mean commuter cars.