M50 (two lane 120 kph) to (three lane 100 kph)

Bullseye1

Can someone explain the logic? I realise there are some road works still continuing but there are massive lenghts of the M50 now complete and still 100 kph. Is this permanent?

Mr. Presentable

It's permanent. The lanes are narrower now.

Misticles

I read in another forum on here (possibly motors) that when it's 3 lane, it has to be 100kph to comply with EU regulations.

Bullseye1

Ah the NRA strikes again.:p

marmurr1916

Misticles wrote: »

I read in another forum on here (possibly motors) that when it's 3 lane, it has to be 100kph to comply with EU regulations.

Not true at all. There are no EU regulations about speed limits.

The main reason is traffic congestion and the narrower lanes.

When there are traffic jams, slowing down and allowing a space to develop between you and the traffic ahead eases congestion:

http://amasci.com/amateur/traffic/trafexp.html

Having a lower speed limit in place should (theoretically) help congestion, as long as there aren't too many impatient and bad drivers.

BluntGuy

100 km/h is more than sufficient for that stretch of busy urban motorway. I don't personally think 120 km/h is dangerous, but I can see their logic.

That said, there is no need to reduce it any further. Variable speed limit signs should be used for reducing the limit.

Sponge Bob

4 lanes including the junction hopper lanes actually.

Pete_Cavan

When you consider that the M50 is relatively short (45km), with a lot of junctions (17) and the amount of traffic that uses it, 100kph is sufficient.

Bullseye1

I'm sorry but if you are spending hundreds of millions of Euros on upgrading the road to three lanes and in some places four lanes and you reduce the speed then that's a huge waste of money. That road is well capable of taking 120 kph. And now they are placing cameras on a motorway to shoot fish in a barrell. Only in Ireland.

veryangryman

Bullseye1 wrote: »

I'm sorry but if you are spending hundreds of millions of Euros on upgrading the road to three lanes and in some places four lanes and you reduce the speed then that's a huge waste of money. That road is well capable of taking 120 kph. And now they are placing cameras on a motorway to shoot fish in a barrell. Only in Ireland.

Where do you get off with that "only in Ireland" nonsense?! Have you ever driven in Motorways in the UK? The speed limit drops to 100KPH (sometimes lower) at busy junctions.

The grass aint any greener elsewhere. Not in terms of speed limits. Sorry if this sounds a bit personal but please do your research before posts like that. I mean that in the nicest way possible.

FWIW I have done 120 on the new M50 but you cant do that at peak hours. Far too busy and too many people overtaking on left/driving in wrong lane etc to make it work then. 100 is a realistic overall speed limit

Bullseye1

I guess I get off with that comment as an Irish person paying my taxes only to see it wasted by poor decisions. I don't care what goes on in the UK I don't pay taxes there.

BTW be careful drivng at 120 with those speed cameras.

bkehoe

Not only in Ireland.

Take Berlin, all the Autobahns around the city have an 80km/hr limit! :eek:

serfboard

Bullseye1 wrote: »

I guess I get off with that comment as an Irish person paying my taxes only to see it wasted by poor decisions.

It's not a poor decision - it's a decision taken on grounds of safety - and rightly so.

There have been plenty of poor decisions taken on road construction/development in this country, but this is not one of them.

Ren2k7

100 KPH may be the new speed limit but you'd be hard pressed to find many motorists travelling at that speed on the M50, myself included.

Bullseye1

serfboard wrote: »

It's not a poor decision - it's a decision taken on grounds of safety - and rightly so.

There have been plenty of poor decisions taken on road construction/development in this country, but this is not one of them.

Your opinion and your perfectly entitled to it but as somekne who has worked on road construction it's one of the worst ones made in this country along with the Kilmacanogue duel carriageway which has one of the most danergous petrol station entrances in the country.

L1011

Bullseye1 wrote: »

Your opinion and your perfectly entitled to it but as somekne who has worked on road construction it's one of the worst ones made in this country along with the Kilmacanogue duel carriageway which has one of the most danergous petrol station entrances in the country.

Beaufort S/S eastbound on the N7 beats it, pitted potholed entrance straight on to a 100km/h three lane DC...

duckysauce

are there any working speed cams on the m50 at the mo ?

KevR

The 100kmh limit is annoying when there is very little traffic on the M50 (i.e. - I see no problem with doing 120kmh on it at 1am for example) but when it's even a little busy then I think the 100kmh limit is more appropriate. They need a Variable Speed Limit system.


PS - I find the 80kmh limit on the Lucan Bypass a lot more annoying than the M50 limit. It's really difficult to stick to 80kmh along the Lucan BP; in my opinion the limit should be 100kmh.

Tragedy

Variable speed limits please.
At peak times, 80km/h would be very beneficial at a lot of junctions, likewise 120km/h at night is absolutely fine.

civildefence

I believe the digital speed limit signs seen elsewhere are the answer. Alternating between 80/100/120 depending on traffic and road conditions and of course they would be a massive help to drop the limit to 50 in fog

Jayuu

KevR wrote: »

The 100kmh limit is annoying when there is very little traffic on the M50 (i.e. - I see no problem with doing 120kmh on it at 1am for example) but when it's even a little busy then I think the 100kmh limit is more appropriate. They need a Variable Speed Limit system.


PS - I find the 80kmh limit on the Lucan Bypass a lot more annoying than the M50 limit. It's really difficult to stick to 80kmh along the Lucan BP; in my opinion the limit should be 100kmh.

Totally agree with both points. While I can appreciate a lower speed limit on the M50 during the day as its quite busy and the lanes are narrow is places, it makes no sense once you get beyond eight in the evening and there is much less traffic on the road.

As for the N4 at Lucan/Leixlip, this is probably the craziest speed limit in the country. I drive most of it every week as far as Junction 4 and I don't see any cars observing the limit. And a couple of weeks ago some guy beeped his horn at me because I was trying to keep to the limit in the inside lane and clearly he felt that I was going too slow!!! Needless to say I took it with my usual grace and panache (NOT!).

Actually I got two penalty points some years ago here because I was too slow in changing down from the 120kmh limit on the M4 motorway to 80kmh N4 limit. Its a very abrupt change. Therefore I was going at 97kmh (under 60mph for those who want the conversion) at twenty past two in the morning and was caught by some speed camera.

Empire o de Sun

That speed camera was well known I thought. But I don't know if its still there post rebuild.

In germany, where allot of motorways have no speed limit. There will be limits at large and/or busy intersections. And the limit can go down to 100 km/h, on urban motorways in germany as stated before it can be 80 km/h.

While many don't agree with the limit, the slower speed increases capacity and prevents so many phantom traffic jams happening, these are traffic jams for no apparent reason, where the road is at saturation point (exceeded capacity) and one car brakes for only a second, causing a ripple effect where eventually the traffic stops.

Unfortunately Irish legislation probably doesn't allow for variable speed limit signs. The M50 could probably do with this. In the same way Irish legislation doesn't allow a 90 km/h sign, which could be used for the Lucan bypass.

Irish and Proud

veryangryman wrote: »

Where do you get off with that "only in Ireland" nonsense?!

+1

...there's that saying:

Hills are green when they're far away!

veryangryman

Bullseye1 wrote: »

I don't care what goes on in the UK I don't pay taxes there.

The point is that a busy city (regardless of whether you pay your taxes or not) that has an orbital Motorway is going to have busy roads.

Busy road = more risky.
Narrower lanes = more risky
More risky = lower speed limit

The only solution would be to widen the lanes but since that aint happening anytime soon I cant see the need to bad-mouth the politicians (this time)

murpho999

Just to put some perspective on it.

M50 is 45km long.

If travelling at 100km you will drive it in 27 minutes.
If travelling at 120km you will drive it in 22.5 minutes.

Difference is 4.5 minutes.

Now who is such a hurry and arguing over 4 and half minutes?

Here is a logical explanation for speed limits on Wikipedia.

The original speed limit on the M50 was 70mph (112km/h) which was increased to 120km/h when all speed limits in the Republic of Ireland became metric in 2003. The Southern Cross Route (the extension from Junction 12 to Junction 14, and later to Junction 17) was given a lower limit of 60mph (96km/h) with a decimal limit of 100km/h after 2003. This was because of its more undulating terrain, tighter and more frequent curves and resulting shorter sight lines. Because of the doubling of the number of running lanes along most of the route, which has shortened sight lines and increased lane changing, and due of the high number of junctions, the entire length of the route has (with the exception of the section from Junction 1 to Junction 3) the same speed limit, of 100km/h, since it was completely upgraded (2007-10).

Tragedy

murpho999 wrote: »

Just to put some perspective on it.

M50 is 45km long.

If travelling at 100km you will drive it in 27 minutes.
If travelling at 120km you will drive it in 22.5 minutes.

Difference is 4.5 minutes.

Now who is such a hurry and arguing over 4 and half minutes?

Let's make the speed limit 80km/h, who is in such a hurry and arguing over 7 minutes?

Let's make it 60km/h in fact.

Very logical.

L1011

Wikipedia article has had any reference to the remaining 120km/h section removed, again.

murpho999

Tragedy wrote: »

Let's make the speed limit 80km/h, who is in such a hurry and arguing over 7 minutes?

Let's make it 60km/h in fact.

Very logical.

Your user name is very appropriate for your post.

The speed limit on M50 is correct, especially when considering amount of traffic and no of exits/entrances.

Come up with an argument in favour of 120kph instead of just dissing a post with no actual valid point.

L1011

civildefence wrote: »

I believe the digital speed limit signs seen elsewhere are the answer. Alternating between 80/100/120 depending on traffic and road conditions and of course they would be a massive help to drop the limit to 50 in fog

The gantries for these are already installed along the entire M50; but there appears to be no intent to use them...

Tragedy

murpho999 wrote: »

Your user name is very appropriate for your post.

The speed limit on M50 is correct, especially when considering amount of traffic and no of exits/entrances.

Come up with an argument in favour of 120kph instead of just dissing a post with no actual valid point.

100kp/h isn't correct at peak times, and it isn't correct at off peak times. I'd struggle to find a time it is correct at to be honest.

It's a compromise, it's not correct in any way though. I also did come up with a valid argument in favour of 120km/h, it's variable speed limits like on busy motorways in many countries.

Thanks for your informed reply, and don't forget to read my post a few above yours where the aforementioned post on variable speed limits is there for all to read