N-XX Road Signs

E92

Sorry that I have no pics of it, but there are these small road signs (usually on the older N roads) and they say the following for example,

N-20
0302

or
N-71
0000


They are yellow in colour and appear every so often on the left hand side of the road. Now what I want to know is what do the bottom numbers mean? The N-XX means the name o the road, eg N8, N20 etc. But what do the numbers beneath mean?

murphaph

E92 wrote:

Sorry that I have no pics of it, but there are these small road signs (usually on the older N roads) and they say the following for example,

N-20
0302

or
N-71
0000


They are yellow in colour and appear every so often on the left hand side of the road. Now what I want to know is what do the bottom numbers mean? The N-XX means the name o the road, eg N8, N20 etc. But what do the numbers beneath mean?

They are 'chainage markers' which show distances along the road. You can see the very start of the N32 below, N32 0000:

RadioCity

There a handful of these on the M1, on part of the Balbriggan Bypass that show "N 01"!!

murphaph

RadioCity wrote:

There a handful of these on the M1, on part of the Balbriggan Bypass that show "N 01"!!

That is correct. The M1 is legally still the N1.

RadioCity

So the M1 is nothing more than a dual carriageway with blue signs?

murphaph

RadioCity wrote:

So the M1 is nothing more than a dual carriageway with blue signs?

There's a bit more to it than that but pretty much, yeah.

Zoney

As far as I know, they are along *all* N roads in the country - including those that are partly motorway. One can see both N07 and N09 markers in close proximity at the M7/M9 junction heading eastbound on the M7.

I presume the M50 has them too - with N50 on the markers.

RadioCity

I did read somewhere (might have been here) that the M50 is indeed the N50, and was given the M as it was motorway standard anyway.

Equally the N32 is apparently the M32....confusing, yes.:rolleyes:

murphaph

Zoney wrote:

I presume the M50 has them too - with N50 on the markers.

Yeah, but the only one I remember seeing was obliterated during the works. I presume they'll be replaced!

MDTyKe

Yea, all roads are N officially. The road designation is at least. When motorway legislation is brought in for part of it, then it gets the designation M1 to show the difference to road users - but the route is still 'N1' when used in legal papers etc.

And maybe those signs are some sort of distance markers? Maybe if you're in an emergency on the motorway for example, you look to the nearest sign to tell the operator what marker you're closest to?

godtabh

What is the chainage measured in?

If memory serves me if its meters some of these roads could be 500 km + but no single length of road is more than that (or is it).

So does it say measure from the start of the N7 and were it branches off to the N9 continue on?

Unless I'm reading these signs total arse ways

mike65

Aren't they put up for logistical reasons?

Mike

murphaph

kearnsr wrote:

What is the chainage measured in?

If memory serves me if its meters some of these roads could be 500 km + but no single length of road is more than that (or is it).

So does it say measure from the start of the N7 and were it branches off to the N9 continue on?

Unless I'm reading these signs total arse ways

they are weird units iirc, something like 10m increments.

icdg

Zoney wrote:

I presume the M50 has them too - with N50 on the markers.

That's an interesting one actually - newer ones on the M50 have "N50" on them, but ones on the Western Parkway (or the ones that haven't been obliterated by the works) have/had "M50" on them instead. Unlike the rest of the motorways in the country, the M50 existed before it was a national primary route (first section opened in 1990, but the N50 did not exist until 1994 after the passage of the Roads Act 1993).

MDTyKe wrote:

And maybe those signs are some sort of distance markers? Maybe if you're in an emergency on the motorway for example, you look to the nearest sign to tell the operator what marker you're closest to?

These are actually being put up in England for this purpose I believe, but they're a lot bigger than our chainage markers.

Del2005

Don't motorways have makers on then pointing you to the nearest emergency phone? And they are supposed to be 1km apart. The motorway signs are different to the chainage markers as the chainage ones appear to be placed at random on the roads.

Victor

Chainage markings usually start at zero on a project and move up. If several unrelated projects are carried out on one route, the number may be reset along the way. Where one project follows from the end of a previous project, the numbering may be continued.

Rovi

murphaph wrote:

they are weird units iirc, something like 10m increments.

Chain-
http://en.wikipedia.org/wiki/Chain_%28unit%29

spacetweek

>they are weird units iirc, something like 10m increments.

Rovi wrote:

Chain

You're both right. There are 3 chains, the traditional British one which was 22 yards, the modern American one which seems to vary, and the modern one used elsewhere which appears to be either 1 metre or 10 metres. I'm about 95% sure the unit used on those little signs is 10 metres. In any case it is definitely not non-metric.

JackieChan

I've seen markers on the Calais-Paris motorways(in central resevervation).
From memory they were marking ever 100m. Are these common throughout France/the Continent?

godtabh

spacetweek wrote:

>they are weird units iirc, something like 10m increments.

You're both right. There are 3 chains, the traditional British one which was 22 yards, the modern American one which seems to vary, and the modern one used elsewhere which appears to be either 1 metre or 10 metres. I'm about 95% sure the unit used on those little signs is 10 metres. In any case it is definitely not non-metric.

Chainages can be done in any increment be it 5m, 10m 100m etc it all depends on the job and what its been used for

Brian CivilEng

OK, those chainage plates are kind of measured in miles. Say if the chain indicated is N07 - 0523, it means that you are 52.3 miles from the beginning of the N7. To specify a location on the road, you count in metres from the nearest chainage plates, for instant you could specify the location of a culvert that is 400m after the plate as N07 - 0523 + 400.

Victor

abitofacomedian wrote:

OK, those chainage plates are kind of measured in miles. Say if the chain indicated is N07 - 0523, it means that you are 52.3 miles from the beginning of the N7.

Are you certain?

jrar

JackieChan wrote:

I've seen markers on the Calais-Paris motorways(in central resevervation).
From memory they were marking ever 100m. Are these common throughout France/the Continent?

Any French autoroute I've ever been on have had red/white markers indicating every km, and some have signs showing the increments in 100 metres or else they have the meterage painted on the road inside the hard shoulder, or indicated by a small white marking perpendicular to the side markings (called "traites" I believe)

I've seen similar on other motorway networks throughout Europe - in Spain, addresses on such roads often carry a reference to the nearest km marking, as they do on Rural Routes in the US. Mightn't be consistently the same in all cases, but commonly used where motorway/highway networks exist

Very useful for pinpointing accidents to emergency services, or warning drivers of ice/oil/obstructions etc.

tonc76

abitofacomedian wrote:

OK, those chainage plates are kind of measured in miles. Say if the chain indicated is N07 - 0523, it means that you are 52.3 miles from the beginning of the N7. To specify a location on the road, you count in metres from the nearest chainage plates, for instant you could specify the location of a culvert that is 400m after the plate as N07 - 0523 + 400.

The signs are increments of 10m so N07 0523 os 52.3km from the beginning of the N07

godtabh

abitofacomedian wrote:

OK, those chainage plates are kind of measured in miles. Say if the chain indicated is N07 - 0523, it means that you are 52.3 miles from the beginning of the N7. To specify a location on the road, you count in metres from the nearest chainage plates, for instant you could specify the location of a culvert that is 400m after the plate as N07 - 0523 + 400.

That makes no sense. You give a location of something in meters and miles. Genearlly one unit is used in measurements be it metric or imperial and in nearly all cases its metric.

godtabh

tonc76 wrote:

The signs are increments of 10m so N07 0523 os 52.3km from the beginning of the N07

That makes more sense

Brian CivilEng

Unless they have replaced them all in the last few years, they are indeed specified in miles. I remember the one that was located outside the church in portlaoise had something in in the early 500s on it. Portlaoise in 80km from Dublin, but only 50 miles.

This method of specifying locations has been around longer than the metric system was used here. It is similar to Irish Rail still using mileposts, it's just been grandfathered in. The distance is given in metric to the nearest plate as that is what most cars can measure.

jlang

I remember clocking them as I drove from somewhere to Dublin at being measured in tenths of a mile before, but I assumed I'd made a mistake.