M50 Congestion

First Up

tom1ie wrote:

So first up, you are saying the reason for traffic being so bad on the m50 is not down to volume it’s accidents and bad driving, have I got that right? If so how do you explain the n7 inbound (Dublin bound) traffic? Even with the 3 lanes the traffic is back to Naas with no accidents occurring. Would this have anything to do with volume?

If course it does, although traffic all the way back to Naas would usually require more than just volume.

My experience of the M50 is that most (and the longest) delays are due to accidents.

Stark

It's getting really black and white, the discussion here.

First off, few road traffic accidents are genuine accidents. Most can be attributed to some behaviour which could be changed with better education/enforcement.

You can't eliminate them entirely but there are things you can do to reduce the number of incidents. For example, average speed cameras and variable speed limits that adjust according to traffic volumes.

Traffic volumes and "accidents" do go hand in hand. As traffic volume goes up, so do the number of accidents. Above a certain volume, it is no longer safe to do 100km/hr or 120km/hr. The likes of the N7 and M50 are currently operating above the safe design threshold at rush hour. Variable speed limits are probably the best way to counteract this effect.

First Up

CowboyTed wrote:

Still not working...

Stark wrote:

First off, few road traffic accidents are genuine accidents. Most can be attributed to some behaviour which could be changed with better education/enforcement.

All road accidents are the result of behaviour. "Accident" just means the result was not intended or anticipated.

Thargor

First Up wrote: »

How about the solution to road traffic accidents is to not do the things that cause them?

Do you need help compiling a list?

Have you thought about writing to the RSA with your amazing plan to eliminate road traffic accidents? It's very selfish of you to keep your ingenious 'Dont Have Traffic Accidents' theory to yourself when it could be saving lives right now. If you pm me your address I'll send you a box of crayons so you can get your proposal down on paper.

MJohnston

Stark wrote: »

It's getting really black and white, the discussion here.

Alright, then let's get nuanced:

• You can probably reduce some temporary congestion events with greater enforcement of speed limits, and you can solve some more by lowering the M50 peak speed limits to 80 or lower.
  
• A lot of the congestion-causing bad driving on the M50 is due to driver behaviours that are 100% legal.
  
• Even setting aside driver behaviour for a minute, breakdowns are neither illegal, nor preventable. And they're more frequent and just as disruptive as accidents.
  
• I don't believe that even without breakdowns and accidents that the M50 would be un-congested. It clearly exceeds capacity during peak hours.
  
• More dangerous driver behaviour is going unenforced in parts of the city centre that include vulnerable road users such as pedestrians or cyclists. This behaviour doesn't just cause congestion, it injures and kills people.
  
• There is not an infinite budget available to police the roads, and you can't automate for every bad driver habit, so you have to balance your resources carefully.
  
• Most would argue that the off-motorway enforcement is more urgent and deserving of policing resources.
  
• Even with all the enforcement in the world on the M50 and exit roads, you still have the problem that a lot of congestion is not caused by illegal driving.

So even with all that, I'm afraid I still come to two pretty solid conclusions:

1. Increased enforcement on the M50 will not solve the constantly increasing congestion on that road.

2. If resources were available for increased enforcement, they would be needed elsewhere in the city first.

Thargor

First Up wrote: »

Its all a mystery to you eh?

A few driving lessons might help - but I wouldn't book a test until you have figured a few things out.

No its really clear to me now, Im going to use your ingenious theory of how to eliminate traffic accidents to solve all the breakdowns clogging it up every day aswell, all you have to do is tell people not to have breakdowns! It works for traffic accidents in your head...

And as for the road being 20-30% over design capacity (now I know this is nothing to do with delays as you've already proved, it's all those deliberate traffic accidents), we could just tell people to use the road 20-30% less. Problem solved!

monument

People here need to be a nicer to each other or there will be action.

— mod

tom1ie

First Up wrote: »

If course it does, although traffic all the way back to Naas would usually require more than just volume.

My experience of the M50 is that most (and the longest) delays are due to accidents.

Nah. It's exceeded its capacity at peak times. There's your problem.
Solution being reduce usage by providing top class PT.
Sorted.

First Up

MJohnston wrote:

1. Increased enforcement on the M50 will not solve the constantly increasing congestion on that road.

No, but it could reduce the amount of bad driving that is causing the daily accidents on the M50. Enforcement works. Cameras could catch a lot.

MJohnston wrote:

2. If resources were available for increased enforcement, they would be needed elsewhere in the city first.

Why and for what? I'm not arguing against enforcement anywhere but the frequency of accidents and resulting delays on the M50 is a daily occurence. Delays in the city are almost all due to congestion.

magicbastarder

Between the lucan and red cow junctions carries approx 160,000 vehicles per day; averaged out over the year. And I assume that's in both directions. 160k per day is two vehicles a second, or in one direction, one vehicle per second. Given that includes weekend and nighttime traffic, I'm going to - for the laugh - suggest that rush hour traffic is at least twice the average volume. At twice the average volume, you're at one vehicle per lane every two seconds, which is the standard reaction time suggested for safe driving in the dry. If it is more that two vehicles per second, you're pretty much in the danger zone for human reaction times and that's a barrier that's very hard to lift, no matter how you engineer it.

First Up

Thargor wrote:

No its really clear to me now, Im going to use your ingenious theory of how to eliminate traffic accidents to solve all the breakdowns clogging it up every day aswell, all you have to do is tell people not to have breakdowns! It works for traffic accidents in your head...

If you took a few lessons or paid attention to the RSA tv ads you might even learn how to avoid accidents. Breakdowns happen but a hefty fine and towing charge would discourage people with clapped out bangers from taking them on the M50.

Thargor wrote:

And as for the road being 20-30% over design capacity (now I know this is nothing to do with delays as you've already proved, it's all those deliberate traffic accidents), we could just tell people to use the road 20-30% less. Problem solved!

I await your solution for the congestion. In the meantime, why not minimise the problem by an education and enforcement campaign to change the behaviour that causes accidents?

Salary Negotiator

magicbastarder wrote: »

Between the lucan and red cow junctions carries approx 160,000 vehicles per day; averaged out over the year. And I assume that's in both directions. 160k per day is two vehicles a second, or in one direction, one vehicle per second. Given that includes weekend and nighttime traffic, I'm going to - for the laugh - suggest that rush hour traffic is at least twice the average volume. At twice the average volume, you're at one vehicle per lane every two seconds, which is the standard reaction time suggested for safe driving in the dry. If it is more that two vehicles per second, you're pretty much in the danger zone for human reaction times and that's a barrier that's very hard to lift, no matter how you engineer it.

You can get actual figures here.

https://www.nratrafficdata.ie/c2/gmapbasic.asp?sgid=ZvyVmXU8jBt9PJE$c7UXt6

First Up

magicbastarder wrote:

Between the lucan and red cow junctions carries approx 160,000 vehicles per day; averaged out over the year. And I assume that's in both directions. 160k per day is two vehicles a second, or in one direction, one vehicle per second. Given that includes weekend and nighttime traffic, I'm going to - for the laugh - suggest that rush hour traffic is at least twice the average volume. At twice the average volume, you're at one vehicle per lane every two seconds, which is the standard reaction time suggested for safe driving in the dry. If it is more that two vehicles per second, you're pretty much in the danger zone for human reaction times and that's a barrier that's very hard to lift, no matter how you engineer it.

True, but all the vehicles are going in the same direction. That suggests that accidents are either rear enders caused by excessive speed or collisions caused by unwise/careless lane changing (possibly combined with excessive speed.) All of these are behavioural and therefore changeable

There could be other contibutory factors, such as the national obsession with sitting in the middle lane which is another example of drivers not knowing how a motorway is supposed to work.

thunderdog

Last week (not at rush hour) I came to a standstill about 500m from the J7 exit (going southbound). Presumed it was the usual accident. Nope it was some guy who had a flat tire who was in the process of changing his wheel in lane 1 just before the road splits for J7 exit. Impressively stupid

magicbastarder

First Up wrote: »

True, but all the vehicles are going in the same direction.

That's the context the two second time covers though, and it's very generally applied for all reasonable speeds.

In short - if you accept my figures, and they were just a very quick calculation - it's not possible for the m50 to carry the volume of traffic it does at rush hour and remain completely safe against incident.

First Up

tom1ie wrote:

Nah. It's exceeded its capacity at peak times. There's your problem. Solution being reduce usage by providing top class PT. Sorted.

And I'm sure you will be happy to pay the higher taxes needed to pay for it.

We could also encourage improved driver behaviour for almost no cost but I suppose that is much too hard.

First Up

magicbastarder wrote:

That's the context the two second time covers though, and it's very generally applied for all reasonable speeds.

Yes but no oncoming traffic, no cars emerging from side roads, no bad bends or any of the other structural contributors to accidents on lesser roads.

It is just bad/inappropriate driving for the conditions.

magicbastarder

I'm not arguing against decent policing of idiot driving btw, far from it - but I suspect there would be a backlash against it, certainly in the short term in that policing someone doing something stupid on the m50 could itself result in congestion. How do you do someone for changing lanes abruptly and without indicating, without pulling them over?

First Up

magicbastarder wrote:

I'm not arguing against decent policing of idiot driving btw, far from it - but I suspect there would be a backlash against it, certainly in the short term in that policing someone doing something stupid on the m50 could itself result in congestion. How do you do someone for changing lanes abruptly and without indicating, without pulling them over?

Cameras. Ticket in post. Same as speeding.

magicbastarder

Speeding is easy, it's a quantitative measurement. But a lot of the bad driving would be qualitative, surely? Would need a human watching the camera to spot the idiocy and flag it?

First Up

magicbastarder wrote:

Speeding is easy, it's a quantitative measurement. But a lot of the bad driving would be qualitative, surely? Would need a human watching the camera to spot the idiocy and flag it?

Its done elsewhere. Start with reviewing accidents; hammer the culprits.

Thargor

First Up wrote: »

If you took a few lessons or paid attention to the RSA tv ads you might even learn how to avoid accidents. Breakdowns happen but a hefty fine and towing charge would discourage people with clapped out bangers from taking them on the M50.



I await your solution for the congestion. In the meantime, why not minimise the problem by an education and enforcement campaign to change the behaviour that causes accidents?

Ah okay so its only bangers that break down not the vast vast majority of cars on the road which have passed their NCT of are too new to need it. You should be the minister for transport the way you cut through the BS and get straight to the heart of the issues. Like how you solved the issue of traffic accidents on the most overcrowded road in the country by suggesting people not have accidents then solved the issue of cars breaking down by telling people not to drive cars that break down.

And I already solved the congestion issue, I used your methodology, we just have to tell people not to drive on congested roads remember? Forget about public transport or provision of cycling infrastructure to relieve congestion or any of that eurotrash, it's all the traffic accidents that are the problem, people just aren't doing what you tell them.

tom1ie

First Up wrote: »

And I'm sure you will be happy to pay the higher taxes needed to pay for it.

We could also encourage improved driver behaviour for almost no cost but I suppose that is much too hard.

I would be happy to pay higher taxes if I got an appropriate level PT and for example health service in this country.

It's not one or the other, which you are implying, it's education and providing an alternative.

First Up

tom1ie wrote:

It's not one or the other, which you are implying, it's education and providing an alternative.

I'm implying no such thing. Of course we need to address many things but providing an alternative to an orbital motorway is neither simple or quick and it certainly isn't cheap.

But we could greatly improve the effectiveness of the current infrastructure by using it properly. I'm curious why such a straightforward point arouses such hostility.

MJohnston

magicbastarder wrote: »

Speeding is easy, it's a quantitative measurement. But a lot of the bad driving would be qualitative, surely? Would need a human watching the camera to spot the idiocy and flag it?

I'd argue that most of the congestion causing driver behaviour isn't even close to being an enforceable offense.

Breaking too early when the car in front slows? Not enforceable.

Merging without being at full speed? Not enforceable.

Middle lane hogging? Mostly unenforceable, usually not even close to illegal. Definitely not enforceable with fixed cameras.

First Up

MJohnston wrote:

Breaking too early when the car in front slows? Not enforceable.

No, but running into the rear of the car in front is. The responsibility is with the car behind, same as everywhere else.

MJohnston wrote:

Merging without being at full speed? Not enforceable.

The speed of merging is a judgement call.

MJohnston wrote:

Middle lane hogging? Mostly unenforceable, usually not even close to illegal. Definitely not enforceable with fixed cameras.

I've heard of cops on bikes pulling lane hoggers over but its rare unfortunately. Its an education thing mostly; RSA run a TV ad but not often enough obviously!

MJohnston

First Up wrote: »

No, but running into the rear of the car in front is. The responsibility is with the car behind, same as everywhere else.


The speed of merging is a judgement call.



I've heard of cops on bikes pulling lane hoggers over but its rare unfortunately. Its an education thing mostly; RSA run a TV ad but not often enough obviously!

But my point is that these things are likely causing the vast majority of congestion on the M50, or at least the congestion that isn’t caused by congestion on exit routes.

And so, again we come back to the prime issue - you won’t solve M50 congestion with increased enforcement.

First Up

MJohnston wrote:

But my point is that these things are likely causing the vast majority of congestion on the M50, or at least the congestion that isn’t caused by congestion on exit routes.

I described two recent journeys; one to Clondalkin that took 25 minutes and one to Lucan that took one hour 45. Same time of evening (6.30), same amount of traffic. Only difference was accidents on one and none on the other.

There will always be congestion at peak times but gridlock only occurs with accidents.

cdaly_

First Up wrote: »

But we could greatly improve the effectiveness of the current infrastructure by using it properly. I'm curious why such a straightforward point arouses such hostility.

So, lets start with:

• Stopping at red lights.
• Not driving in bus lanes ("because I'm turning left 2km ahead").
• Staying off yellow boxes*.
• Not blocking junctions in a tailback.
• Not parking on footpaths.
• Not driving on footpaths.
• Not parking on cycleways.
• Not driving on cycleways.
• Not parking in hard shoulders.
• Not driving in hard shoulders.
• Maintaining a safe distance to the vehicle in front.
• Using merge lanes correctly.
• Watching the road instead of your phone.
• Changing lanes in good time.
• Changing lanes safely with good observation.

I suspect much of the 'hostility' arises from some posters' refusal/inability to understand that private cars are the most inefficient use of limited commuting space and that an insistance that the solution lies in improving the motorway is the only way forward.


*Interestingly, I pretty much never see people stopped in the yellow boxes at railway crossings. I wonder why? Maybe it's because they know there are consequences...

cdaly_

cdaly_ wrote: »

*Interestingly, I pretty much never see people stopped in the yellow boxes at railway crossings. I wonder why? Maybe it's because they know there are consequences...

Hah!

https://twitter.com/IrishRail/status/1200351340976844800
https://twitter.com/IrishRail/status/1200420004593885184

Twice today!...

MJohnston

First Up wrote: »

I described two recent journeys; one to Clondalkin that took 25 minutes and one to Lucan that took one hour 45. Same time of evening (6.30), same amount of traffic. Only difference was accidents on one and none on the other.

There will always be congestion at peak times but gridlock only occurs with accidents.

How do you know that was the only difference? From the one difference that you yourself witnessed? That's not enough to state that it's the *only* difference.

Fundamentally, you are simply wrong to say that gridlock only occurs with accidents. Among other sources of gridlock I can think of are:
* breakdowns (in fact, I'd warrant that this is a far more frequent contributor to gridlock on M50 than accidents)
* random road debris
* accordion congestion (https://www.vox.com/2014/11/24/7276027/traffic jam)
* congestion on exit roads off the M50
* low-visibility congestion due to heavy rain, fog, etc.

Again we come back to this simple fact - the M50 is usually operating at or above maximum capacity. Any approach that doesn't take cars off of the road and keep them off will not solve this problem. I'm confident that's as close to outright fact as an opinion can get.

First Up

MJohnston wrote:

How do you know that was the only difference? From the one difference that you yourself witnessed? That's not enough to state that it's the *only* difference.

Because the accidents were both reported on the radio. Nothing else was.

MJohnston

First Up wrote: »

Because the accidents were both reported on the radio. Nothing else was.

I...don't...are you...seriously?

Dravokivich

Rubberchikken wrote: »

maybe planners will need/be able to design roads with a lane only for vehicles with more than 1 occupant.

the number if single occupant cars is a symptom of of dire public transport/unwillingness of many to engage with the one we already have/and a desire to seal ourselves away from the world behind our car doors.

A lot of new roads built between Grange Castle and Newcastle recently. Clearly they were done to support the developement of business parks in the area. But with only single lane traffic. Should have been designed and produced with Bus Lanes in mind, to assist with commuting, but didn't.

How are we meant to get around, if the IDA, Councils and Transport Planners are not willing to set up effective infrastructure to support it? Especially when they've nothing in place preventing them from doing it!

First Up

A postscript to the recent exchanges;
I used the M50 from Stillorgan to Lucan at 18.30 last evening. No accidents and traffic flowed freely. I saw a small queue at the exit for the N7 but nothing serious. My total journey time about 30-35 minutes.

The lesson - cut out the stupid accidents and the M50 will do the job it was built for.

MJohnston

18:30 is a bit late in the day to be using as anecdotal evidence of M50 peak operation.

First Up

MJohnston wrote:

18:30 is a bit late in the day to be using as anecdotal evidence of M50 peak operation.

There was lots of traffic. Most of the long delays I've experienced have been between 18.30 and 19.30

MJohnston

Naw, the evening peak is between 1530 and 1830 according to TIIs data:
https://www.tii.ie/tii-library/strategic-planning/nra-road-network-indicators/TII-National-Roads-Network-Indicators-2018.pdf

And the specific peak is sometime around 5pm, as you'd expect. Traffic after 1800 drops significantly from that peak.

First Up

MJohnston wrote:

And the specific peak is sometime around 5pm, as you'd expect. Traffic after 1800 drops significantly from that peak.

So what accounted for the one hour + tailbacks I've endured 18.30 -19.00?

MJohnston

First Up wrote: »

So what accounted for the one hour + tailbacks I've endured 18.30 -19.00?

Traffic.

First Up

MJohnston wrote:

Traffic.

But you said traffic eases considerably by then.

trellheim

No, he was referring to the hard data gathered by the NRA/TII as linked above https://www.tii.ie/tii-library/strategic-planning/nra-road-network-indicators/TII-National-Roads-Network-Indicators-2018.pdf see page 15


its not an opinion its a fact.

First Up

trellheim wrote:

No, he was referring to the hard data gathered by the NRA/TII as linked above

Which says there is less traffic after 18.30 which is fair enough. This was offered to explain why I was able to make a journey in 35 minutes last evening. But when I described the same journey at the same hour and same volume of cars taking 90-115 minutes, the explanation offered was "traffic".

MJohnston

First Up wrote: »

Which says there is less traffic after 18.30 which is fair enough. This was offered to explain why I was able to make a journey in 35 minutes last evening. But when I described the same journey at the same hour and same volume of cars taking 90-115 minutes, the explanation offered was "traffic".

I'm not sure what's tricky about this? There's lots of traffic at 1830. There's even more traffic at 1700.

First Up

MJohnston wrote: »

I'm not sure what's tricky about this? There's lots of traffic at 1830. There's even more traffic at 1700.

You seem to be finding it tricky to explain what changes a journey from 35 minutes to 115 under the same time, road and traffic volume conditions.

MJohnston

First Up wrote: »

You seem to be finding it tricky to explain what changes a journey from 35 minutes to 115 under the same time, road and traffic volume conditions.

No, what's tricky is you seem to think it could only be caused by a single thing.

First Up

MJohnston wrote:

No, what's tricky is you seem to think it could only be caused by a single thing.

You can nominate as many possible causes as you can dream up.

I have instanced journeys that took me 35 minutes and as long as 115 minutes. One difference between those journeys was no accidents on the former and one or more accidents on the latter.

I find that a fairly strong causal relationship but your alternative theories are welcome.

magicbastarder

it's not that accidents cause congestion, and that's the end of it.
accidents cause congestion, but congestion causes accidents. of course the traffic was more free flowing when there were no accidents, that's a trivial statement. it's just that an accident will cause congestion, no question about it, but congestion causing accidents is more of a probability than a definite.

First Up

magicbastarder wrote:

it's not that accidents cause congestion, and that's the end of it. accidents cause congestion, but congestion causes accidents. of course the traffic was more free flowing when there were no accidents, that's a trivial statement. it's just that an accident will cause congestion, no question about it, but congestion causing accidents is more of a probability than a definite.

How does congestion cause accidents?

donvito99

First Up wrote: »

How does congestion cause accidents?

This question asked in a thread about the M50, ladies and gentlemen.