N8/N25/N40 - Dunkettle Interchange [under construction]

Agreed. It seems the only people who don't see that the current signage is poor are those responsible for putting it up in the first place.

The problem is simple - Dublin traffic needs to exit right, but is being mistakenly directed into the left lane. Here’s my two hours of thinking about this yesterday. It’s actually a nasty thing to try to produce signage for, as there’s a right-diverge, which is an exceptional thing and needs to be called out better than the current signs do it.

On approach, there’s too much information, and there’s a misdirect that could send drivers for Cork up the Tunnel escape lane. Here’s the existing sign:

Really, all that drivers need to know here is which lane to be in. To do this properly needs a slightly taller gantry sign on the approach to the tunnel, but the resulting sign area will be narrower, and it points only to the two traffic lanes - no danger of anyone taking the escape lane by accident, thinking it will bring them to Cork.

The existing sign misdirects Little Island traffic, which will have a much easier passage through the interchange if it comes out of the tunnel in the left lane. I’ve had to sacrifice the information that Waterford traffic can actually be in either lane for the sake of simplicity, but the right lane is probably a better choice here, to balance the use of the tunnel lanes. And anyway, local drivers will learn the truth soon enough, and they’re not the audience anyway: road signage is for drivers who’ve never been here before.


At exit from the tunnel, the existing signs give technically wrong instructions. The use of diagonal arrows here for Cork is flat out incorrect: panels with this arrow type are supposed to hang over the start of a diverging lane, but there there is no diverging lane at this point for either option. Luckily, drivers aren’t really aware of what this kind of sign means, otherwise you’d see more people entering the yellow area to the left - which pinches down to about 0.5 metres before the actual exit lane starts. The “DUBLIN” panel is confusing because sign is situated just at the emergency median break, it could result in drivers accidentally steering into that area by mistake - I think it’s actually a blessing that its shape and positioning makes it hard to see, but the real problem here is that “DUBLIN” spans two lanes, which sets drivers up for a nasty surprise just 100 metres down the road...

Here’s my suggested change - same area, but just two signage boards:

I know the combination of a lane-arrow and an "exit ahead" upward right arrow on the blue patch is non-standard, but I think it conveys the meaning well: “stay in this lane, you will exit to right”. Changing the DUBLIN board from long and flat to more square also visually ties it to the actual lane-diverge sign immediately down the road from it: the driver now has a trail of “blue square” to follow in order to reach the motorway, which the previous sign design didn’t provide.

On a side note, there’s nothing in the signage manual about patching local (black on white) destinations on national-road gantry signage. I do not believe “LITTLE ISLAND” should be in a white patch either here or on the approach sign. I’ve preserved it because the following signs use it too, but I’m not sure it’s helpful.

Yeah when you think of it, the people taking the left after the tunnel (Tivoli) need to take the similar level of action as those taking the right out of the tunnel (Dublin), but it's signposted very differently

The problem for me with the sign is that it is trying to do too much as well as being badly laid out.

Really all it should be doing is making sure that Dublin bound traffic is in the right hand lane. The bi-directional sign further on that you can see in KrisW101's image should then do the work to get the Dublin traffic to turn off right on to the M8.

What is frustrating about this is that we have examples of this currently on our roads. This is at the northern end of the M50 where the M1 splits off. On the two lanes on the right hand side both will take you to the City Centre and Dublin Port. Howver those heading on the R132 to go toward Malahide must move into the right hand lane because the exit is off to the right. Further on the lane splits again and at that point the Malahide bound traffic is given its own sign. It's simple and it's clear.

This sign is also probably easier to read because there aren't a multiplicy of colours which I think adds to the level of confusion. It also omits the road numbers on the right-hand sign for space reasons.

I have to say that I find the non-motorway signs with their insistence of using lots of colour splashing for road types very confusing. Fine if you want to colour code the route number but leave the main background in the one colour as we do on the motorway signage.

This would be my proposal for the sign before the split similar to the one above. This is clear and concise and those heading to Dublin would be very clear on what lane they should be in.

Note: For language purists my software wouldn't allow me to put in the fadas on the Irish for "Oileán" and "Áth".

The reason the M50 gantry hasn't got road numbers on the right panel isn't to save space. Route numbers only appear on the bottom of these lane signs if the route will change. Taking the left lanes means joining M1, so that's indicated; staying right means staying on M50 so no route number is shown.

The Dunkettle gantries have route numbers on each panel because N40 terminates north of the tunnel, which means that every onward destination is on a new route.

Fair enough on the route number, I missed that point. However it's still my contention that the Dunkettle sign is trying to do way too much given that most people will see it only for a few seconds. The second solution, putting the blue signage over the right hand lane only, solves that in an instant.

I don't know if the cameras are recorded, but if those responsible for the signs can look back on today's recording between 4:02 pm and 4:06 pm they will see exactly what the issue is.

In the four minute period there were a half dozen drivers who made the last minute dive across from lane 1 of the N40 to the M8

One left it so late that the vehicle actually drove across the hatching, nearly colliding with a vehicle which had already entered the slip to the M8 correctly from lane 2 of the N40.

Nope, they said it is intentional

” Coming in from the East towards the new Interchange, the lanes diverge in various directions, leading to multiple destinations such as Little Island, Dublin, Limerick, Cork City Centre and other parts of Cork. The terms City Centre and Cork are used to guide motorists towards the correct lane in a timely manner, differentiating between those heading for the City Centre and those heading to other destinations around the City e.g. Douglas, Blackrock, Wilton, etc. so that the term Cork is used more generically than City Centre. This is part of the traffic management strategy developed for signing of the Interchange.”