First roads to be declared motorways without a motorway order

Niall1234

ga2re2t wrote: »

For those of you who are hoping for speed limits greater than 120 km/h, I'm afraid you can keep dreaming. The differences between 120 and 140 km/h are more than you think:
Fuel consumption goes up considerably, much more than the 10% that was mentioned earlier. I saw a graph recently on this forum which pointed this out. Governments know this and so will not increase speed limits because of rising oil/energy prices and CO2 emissions.
Your angle/cone of vision decreases giving you less of a chance to see objects (e.g. animals) on the road side.
Although 140 is only 16% faster than 120, energy follows a squared relation so that a car crash at 140 is 36% more damaging than at 120.
Ireland is not a big country. The times gained by going 20 km/h faster are not enough to warrant the increase.

Sorry for being a bore

Have a nice day :rolleyes:

On your first point. HQDC's and Motorways in Ireland are designed to be driven on at a maximum of 160kph. While it is more dangerous to drive at 130kph over 120kph on these roads, it would not be deemed to be actually dangerous.

On your second, its hard to argue with. Although, energy does not have a ^2 relationship with speed. It has a ^2 relationship with acceleration. Hence, its getting up to speed where the energy is spent in this respect.

When at speed, the car expieriences air resistance. If there was no air, or parts expieriencing friction with the ground, the car would not require energy at all to retain velocity. However, drag has a ^2 relationship with velocity.

So, yeah, your basically right in your assumptions.


In a perfect world, there would be no drag and the energy expelled in getting the car up to speed would be regained through an energy recovery braking system as seen in hybrid cars.

trellheim

Although, energy does not have a ^2 relationship with speed. It has a ^2 relationship with acceleration.

just plain wrong.

Kinetic energy, the energy a body has as a result of its velocity

= 1/2 * mass of vehicle *velocity * velocity

nothing to do with acceleration.

Consider : If I am travelling at a constant 50 kph and at a steady speed in a 1000Kg car then I have x amount of Joules of Kinetic energy. as long as I stay at that speed I have that. Nothing to do with acceleration. In a theoretical frictionless environment I will continue to possess this energy.

Niall1234

trellheim wrote: »

just plain wrong.

Kinetic energy, the energy a body has as a result of its velocity

= 1/2 * mass of vehicle *velocity * velocity

nothing to do with acceleration.

Consider : If I am travelling at a constant 50 kph and at a steady speed in a 1000Kg car then I have x amount of Joules of Kinetic energy. as long as I stay at that speed I have that. Nothing to do with acceleration. In a theoretical frictionless environment I will continue to possess this energy.

Sorry, explained it badly. The energy is required to accelerate the car to the speed, but the maintenance of this speed is not related to this and has to do with drag and friction.

Chris_533976

Niall1234 wrote: »

You're saying that the slip roads into and off the old Midleton road would have to be removed ? I agree that these are fairly important and really do take a bit of traffic off the old bridge in the centre of Glanmire.

Ideally of course you'd have a full buterrfly junction like at the red cow but long is that going to take, and is it even possible there.

Definatly keep the sliproads, but dont redesignate them. I know the route through Glanmire fairly well and that old bridge + T junction would be a desperate bottleneck.

NRA told me they are going to do a study this year on how to increase traffic capacity at Dunkettle. More details than that sentence though, I dont know. I did do a sketch a while back of how to grade separate it, but its big, costly and difficult. I hate to say it, but having 1 set of traffic lights on some sliproad (cant remember which) made it a lot simpler

Niall1234

Chris_533976 wrote: »

Definatly keep the sliproads, but dont redesignate them. I know the route through Glanmire fairly well and that old bridge + T junction would be a desperate bottleneck.

NRA told me they are going to do a study this year on how to increase traffic capacity at Dunkettle. More details than that sentence though, I dont know. I did do a sketch a while back of how to grade separate it, but its big, costly and difficult. I hate to say it, but having 1 set of traffic lights on some sliproad (cant remember which) made it a lot simpler

I originally thought they were due to put a few left turn slip roads onto Dunkettle. Did they change their mind ?

ga2re2t

Niall1234 wrote: »

Sorry, explained it badly. The energy is required to accelerate the car to the speed, but the maintenance of this speed is not related to this and has to do with drag and friction.

Sorry mate, but you're just digging yourself into a bigger hole by not being clear. Lets go though it in steps:
1. In accelerating, a car uses energy (from petrol or diesel) to overcome inertia, friction and air drag. As it goes faster it gains kinetic energy.
2. At constant speed, it uses energy (from petrol or diesel) to overcome friction and air drag. Its kinetic energy remains constant.
3. In decelerating, a car uses the energy from friction (brakes and the road) and air drag to help decelerate the car. As it slows down it loses kinetic energy. (this kinetic energy is mostly lost as heat to the brakes, the road and the surrounding air).
4. In a crash, a car goes from its driving speed to 0 in only a couple of seconds. It has to lose all it's kinetic energy in this time frame and it does this by mangling up a car. The occupants also undergo considerable g-forces: a 130 km/h crash over 2 seconds will result in up to 2g's (on top of the 1g from Earth's gravity).

Your point on motorways and HQDC's being designed for 160 km/h doesn't really stand. Engineers almost always design structures with safety features above and beyond what will actually be required of them. If the motorways were designed for 120 km/h then we'd be in big trouble! A 160 km/h design ensures safety for the majority of road users even under circumstances where some drivers are breaking the limit by 20 km/h or more.

Chris_533976

Niall1234 wrote: »

I originally thought they were due to put a few left turn slip roads onto Dunkettle. Did they change their mind ?

The only recent work was the general widening and addition of traffic lights. The trouble is, with the tunnel, left turn slip roads wouldnt really fit, and the weaving there is bad enough with the nearby Little Island junction. I dunno what they're gonna do with it, maybe I'll try and dig up that sketch I made.

E92

Niall1234 wrote: »

HQDC's and Motorways in Ireland are designed to be driven on at a maximum of 160kph.

This means that ALL HQDCs and Motorways should have a speed limit of 160 km/h then, since they are designed to handle such a speed.

I was never sure what our HQDCs and Motorways were designed for, but now that I am aware of this it makes no sense whatsoever to have a speed limit on many of our Motorway standard roads of just 5/8s i.e. a small bit over 50% of the speed that they were designed to handle.

120 km/h on a HQDC can't come soon enough then. If something is designed for a certain purpose then it is obviously safe to use it for the purpose in which it was intended, so there should be no safety effect at all by having higher speed limits on roads which were designed in the first place to be able to handle high speeds.

The argument about higher fuel consumption is also flawed at best, as driving at 130 km/h uses just half the fuel driving at 10 km/h does. So should we ban driving at 10 km/h and traffic jams then as well:rolleyes:? Thought not.

Chris_533976

Britains motorways have design geometry of 100mph, but yet the speed limit is 70mph.

invincibleirish

E92 wrote: »

This means that ALL HQDCs and Motorways should have a speed limit of 160 km/h then, since they are designed to handle such a speed.

I was never sure what our HQDCs and Motorways were designed for, but now that I am aware of this it makes no sense whatsoever to have a speed limit on many of our Motorway standard roads of just 5/8s i.e. a small bit over 50% of the speed that they were designed to handle.

120 km/h on a HQDC can't come soon enough then. If something is designed for a certain purpose then it is obviously safe to use it for the purpose in which it was intended, so there should be no safety effect at all by having higher speed limits on roads which were designed in the first place to be able to handle high speeds.

The argument about higher fuel consumption is also flawed at best, as driving at 130 km/h uses just half the fuel driving at 10 km/h does. So should we ban driving at 10 km/h and traffic jams then as well:rolleyes:? Thought not.

Pfft if the speed limit was 160/km then you'd always have the fools in their high powered cars just going over the speed limit, like the guys who go just over 80km/100km/120km.

i would not wish to be on the Fermoy bypass with its hills and overtake someone at oh say 120km when some muppet comes up on the outside lane at 160km+ and kills us all


summary

120km speed limits for a motorway? good
160km speed limits for a motorway? bad


/cue arguments about the autobahns/ we are not Germans were Irish remember!

Metrobest

My opinion is that the speed limit should be based on lane width and traffic volumes, so busier areas approaching cities should have lower limits than sections of motorways through open countryside (if there's any of that left in ireland thanks to the spatial planning policies?)

Padraig Mor

Niall1234 wrote: »

The SSR in Cork was never to be upgraded to 120kph. just the Ballincollig Bypass from the Sarsfield Road Roundabout to Ovens. Personally, the whole lot should be a Motorway with a 100 kph limit on it. Nothing drive me more crazy than tractors on the SSR in rush hour. Happens all the time and causes traffic chaos.

Cork County Council published a consultation document last year which including roads with limits to be increased to 120. I'm pretty sure the SRR from Mahon to Sarsfield Road was included in this and 100% sure the N25 from beyond Dunkettle to Carrigtohill was. Sarsfield Rd to Bandon Rd was not included.

BTW, a motorway order would not prevent tractors from travelling on them - unfortunately, as shown by many threads re the M50 in the Motors forum. Personally, I'd ban tractors from them, even as they stand with N designations - but I ain't in charge!

Niall1234

Padraig Mor wrote: »

Cork County Council published a consultation document last year which including roads with limits to be increased to 120. I'm pretty sure the SRR from Mahon to Sarsfield Road was included in this and 100% sure the N25 from beyond Dunkettle to Carrigtohill was. Sarsfield Rd to Bandon Rd was not included.

BTW, a motorway order would not prevent tractors from travelling on them - unfortunately, as shown by many threads re the M50 in the Motors forum. Personally, I'd ban tractors from them, even as they stand with N designations - but I ain't in charge!

Again, that's just down to law enforcement.

I'd say if a tractor drove past a speed check squad car on a motorway, he would ignore it as the tractor wouldn't be breaking the speed limit. I guaruntee you now the Garda would ignore the tractor.

ga2re2t

E92 wrote: »

This means that ALL HQDCs and Motorways should have a speed limit of 160 km/h then, since they are designed to handle such a speed.

Wow, what amazing conclusions you make! Did you get a degree in road traffic management or something similar? Sure we must be all fools, we should of thought of that yonks ago!

I was never sure what our HQDCs and Motorways were designed for, but now that I am aware of this it makes no sense whatsoever to have a speed limit on many of our Motorway standard roads of just 5/8s i.e. a small bit over 50% of the speed that they were designed to handle.

Now you can update the calculation: 160/120 = 3/4. Feel better?

120 km/h on a HQDC can't come soon enough then. If something is designed for a certain purpose then it is obviously safe to use it for the purpose in which it was intended, so there should be no safety effect at all by having higher speed limits on roads which were designed in the first place to be able to handle high speeds.

Ah feck it, you're a genius! Sure who needs safeguards anyhows? I'll write to the ESB to let them know that they can do away with all those green and brown earth wires cos all my appliances were designed to be safe with no chance of a short circuit!

The argument about higher fuel consumption is also flawed at best, as driving at 130 km/h uses just half the fuel driving at 10 km/h does. So should we ban driving at 10 km/h and traffic jams then as well:rolleyes:? Thought not.

Mammy, mammy, mammy! Jim Bob up the road is allowed go to the funfair and he's only 10 and I'm 11! If he can go I should be allowed go!

Being serious, following complaints by transport gury E92, the government plans to allow the use of space-time warp machines in future car designs so that drivers can go instantaneously from 0 to 50 km/h, thus increasing fuel efficiency and decreasing CO2 emmisions.

E92

ga2re2t wrote: »

Now you can update the calculation: 160/120 = 3/4. Feel better?

No because we have loads of HQDCs slapped with a limit of only 100 km/h(only the road to the border and the Finglas Bypass have a limit of 120).
When the M50 gets upgraded it will have a limit all around it of only 100 km/h. And if you read my post you would realise that I said Motorway standard roads i.e. HQDC and obviously Motorways.

What part of a road being designed for 160 km/h don't you get? If it's designed for something then it can obviously handle something. The only reason our Motorways don't have higher speed limits is because all the eco mentalists would have a seizure and we're all meant to be slowing down, because the only thing that counts for road safety is slowing down. Apparently the rest of the rulers of the road don't matter, not even slightly:rolleyes:.

What part of the "road is designed for 160 km/h: therefore it's speed limit should be 160 km/h" don't you understand?

ga2re2t

Interesting, but possibly worthless, debate we're having here. But sure I'll keep on fanning the flames anyhows:

E92 wrote: »

What part of the "road is designed for 160 km/h: therefore it's speed limit should be 160 km/h" don't you understand?

I understand it all. What you don't understand is that engineering a transport structure to safety standards above its operating requirements is not only common practice, it's common sense. Did you not read the post by invincibleirish earlier on? What part of his post did YOU not understand?

Probably the bigger question is why do you want to go faster? Especially considering that one rarely travels long enough distances where an increase in speed limits actually makes a difference, especially on the relatively small island of Ireland.
Do YOU actually NEED to go faster? Why? Do you want 5 mins extra in bed in the morning? Do you need to release some built up tension (work, sex)? Try taking up some sport, martial arts for example, it does wonders. Maybe you have other issues, I couldn't be bothered giving you more examples. Your desire to drive at 160 km/h says more about your personal life than anything else. How does it feel baring your soul to the public on boards.ie? You should try looking for a suitable section in the "Soc" part of boards.ie.

Happy posting!

E92

ga2re2t wrote: »

Interesting, but possibly worthless, debate we're having here. But sure I'll keep on fanning the flames anyhows:


I understand it all. What you don't understand is that engineering a transport structure to safety standards above its operating requirements is not only common practice, it's common sense. Did you not read the post by invincibleirish earlier on? What part of his post did YOU not understand?

Probably the bigger question is why do you want to go faster? Especially considering that one rarely travels long enough distances where an increase in speed limits actually makes a difference, especially on the relatively small island of Ireland.
Do YOU actually NEED to go faster? Why? Do you want 5 mins extra in bed in the morning? Do you need to release some built up tension (work, sex)? Try taking up some sport, martial arts for example, it does wonders. Maybe you have other issues, I couldn't be bothered giving you more examples. Your desire to drive at 160 km/h says more about your personal life than anything else. How does it feel baring your soul to the public on boards.ie? You should try looking for a suitable section in the "Soc" part of boards.ie.

Happy posting!

Oh get off the "moral high ground" and stop trolling. I was going to answer your question but I see no point in feeding trolls(and I've answered it pretty much already), and stop being so condescending about me and my attitudes towards things.

Niall1234

Whats the point of building roads to a 160kph and slapping a 100kph on it.

Its is extreme over engineering and a waste of public money.

E92 in a way has a point. You build something for a purpose and it should fulfill its intended purpose. Slapping 100kph limits on 160kph is stupidity.

Personally, Irish people are simply not ready for 160kph but 130kph as I've said before shouldn't be out of the question.

ga2re2t, I sincerely hope your not one of the "Holier Than Thou" posters on here who seem to tow the government and Traffic Corps line on everything (even some awfully flawed logic) and claims that they've never broken a rule of the road in their life.

E92

Niall1234 wrote: »

Its is extreme over engineering and a waste of public money.

<snip> You build something for a purpose and it should fulfill its intended purpose. Slapping 100kph limits on 160kph is stupidity.

Personally, Irish people are simply not ready for 160kph but 130kph as I've said before shouldn't be out of the question.

Very good points and I agree with all of that, you're after saying what I've been trying to say basically.

I do agree btw with the assertion that the Irish are incapable of going beyond 130 km/h, however if we all copped ourselves on and took our attitudes towards driving more seriously, then there is no reason at all for not having a limit of 160 km/h.

As for the argument about time, well in 2 years time we will have a Motorway/HQDC(though with a bit of luck under Noel Dempsys wonderful idea of reclassifying the HQDCs to Motorways will finally come to fruition) from Dublin all the way to Waterford, Cork, Limerick and Galway, each of these cities is at least 98 miles from Dublin(Cork is 156, Limerick is 122, Galway is 134, and Waterford is 98.5) according to the AA, so the time savings available when we will have these wonderful high quality roads available by having higher speed limits will be a lot more apparent then than now.

Niall1234

It would prob take a seperate test for Motorway driving.

THis could take up to 5 years to complete. Each and every driver would be required to take the test to drive on a Motorway. Give say 5 years for each and every person who wants to take the test to pass it.

After the 5 year period is up, put up the speed limit and block all users who haven't passed the test from Motorways.

Overall it would almost certainly improve our Motorway driving which at times I find, is quite erratic.

ardmacha

It would prob take a seperate test for Motorway driving.

And this in a State that isn't too bothered if people driving on roads have passed any test.

Introducing a 130kmh speed limit is very far down any possible list of issues needing action on Irish roads.

MDTyKe

I wish they'd upgrade the last bit of the N1 into NI; sorry.. reclassify


Matt

Our man in Havana

Not possible as the only alternative non motorway route has been destroyed.

ga2re2t

What I'm saying is simple:

Increasing speed limits to 160 km/h makes little or no sense and shouldn't be under discussion. I believe that we should be discussing the following:

- Bringing HQDC from 100 km/h up to 120 km/h. A case could be made for 130 km/h speed limits but only when the license system is overhauled so that drivers undergo compulsory motorway driving lessons.

- Bringing regional roads that are of national road quality from 80 km/h up to 100 km/h. For example, bypassed national roads which are reclassified as regional roads should be allowed maintain their 100 km/h speed limit if they are of good quality.

- Reducing speed limits on so-called national roads from 100 km/h down to 80 km/h. I was in the Burren last summer and it was litteraly an "only in Ireland" experience - driving on a "national" road no wider than a single lane on a motorway, with twists and turns every 50 metres and a speed limit of 100 km/h!

As I understand it, the 100 km/h speed limit on 160 km/h designed roads was politically motivated. Getting planning permission for a HQDC is easier than getting a motorway order. Also, it gave local L-drivers and farmers less of a reason to protest during the public consultation phase - the government always planned to stab them in the back by reclassifying the HQDC as motorways.

Apologies for the condescending nature, but in all fairness you've put forward ideas as if they're obvious whereas in reality nothing is obvious. Nothing is straightfoward and every decision has consequences, both good and bad. It's a balancing act and you (E92) wish to tip the scales.

Bards

Also, it was Martin Cullen who brough Legislation for this to Cabinet and it just so happened that when it was enacted Noel Dempsey was in Transport.
Noel Dempsey never had a wonderful Idea in his whole life. Just like the E-voting Machines he dreamed up
Just my 2c

Padraig Mor

Niall1234 wrote: »

Again, that's just down to law enforcement. .

Afraid not. They're legally entitled to drive on motorways here once they are *capable* of reaching speeds in excess of 50 km/h. Ridiculous, but there you go.....

murphaph

ga2re2t wrote: »

What I'm saying is simple:

Increasing speed limits to 160 km/h makes little or no sense and shouldn't be under discussion. I believe that we should be discussing the following:

- Bringing HQDC from 100 km/h up to 120 km/h. A case could be made for 130 km/h speed limits but only when the license system is overhauled so that drivers undergo compulsory motorway driving lessons.

- Bringing regional roads that are of national road quality from 80 km/h up to 100 km/h. For example, bypassed national roads which are reclassified as regional roads should be allowed maintain their 100 km/h speed limit if they are of good quality.

- Reducing speed limits on so-called national roads from 100 km/h down to 80 km/h. I was in the Burren last summer and it was litteraly an "only in Ireland" experience - driving on a "national" road no wider than a single lane on a motorway, with twists and turns every 50 metres and a speed limit of 100 km/h!

As I understand it, the 100 km/h speed limit on 160 km/h designed roads was politically motivated. Getting planning permission for a HQDC is easier than getting a motorway order. Also, it gave local L-drivers and farmers less of a reason to protest during the public consultation phase - the government always planned to stab them in the back by reclassifying the HQDC as motorways.

Apologies for the condescending nature, but in all fairness you've put forward ideas as if they're obvious whereas in reality nothing is obvious. Nothing is straightfoward and every decision has consequences, both good and bad. It's a balancing act and you (E92) wish to tip the scales.

+1. Some seriously anomalous speed limits out there. Some councils did make an effort to reclassify according to quality. Fingal upped the northbound carraigeway of the N3 from Blanchardstown Roundabout from 50mph to 100km/h at the changeover. The inbound carraigeway remained at 80 due to the layout. That was sensible. They also reduced the limits around Westmanstown from NSL (60mph) to 60km/h which is about right-twisty regional road (R121) which has extremely poor sight lines due to high walls following road and lots of cyclists and pedestrians.

caster

icdg wrote: »

Athlone-Galway is the major part of the inter-urban network left out, possibly due to the Athlone Bypass needing major work before it can be redesignated.

Is the Athlone bypass the only reason that they're not going all the way to Galway as motorway? I presume Athlone-Galway is high quality dc?

How much work would be needed on the Athlone bypass to get it up to standard? ... Been a while, since I've passed that way....

murphaph

caster wrote: »

Is the Athlone bypass the only reason that they're not going all the way to Galway as motorway? I presume Athlone-Galway is high quality dc?

How much work would be needed on the Athlone bypass to get it up to standard? ... Been a while, since I've passed that way....

Not too much IMO. The left-in-left-out junction at the Roscommon end of the bridge would need modification but the rest of the road is of a high standard.

Victor

You need to appreciate that the road is only one part of the system.

E92 wrote: »

What part of a road being designed for 160 km/h don't you get? If it's designed for something then it can obviously handle something.

Are the (other) vehicles designed to 160km/h and and the drivers trained to drive at such speeds?

Athlone bypass - I think some of the junctions are really tight - the Ballymahon Road and Coosan Point Road junctions are very close together.