Irish Traffic Lights

Ken writes:
[update: the system I call the ‘Irish’ system below, is not distinctive of Ireland at all, as is pointed out in the comments.]

Irish traffic lights differ from ones I have seen elsewhere. The light sequence is Green, Amber, Red, Green,… (unlike for instance, the UK where the lights go Green, Amber, Red, Amber, Green, Amber, … Incidentally, I like the UK’s amber phase before lights go green, because it gives you a moment to get ready to go. I don’t think the amber phase before red is much use at all, since most motorists just treat it as a reason to speed up.)

The distinctive feature of Irish traffic lights, I think, is the way they control the movement of separate streams of turning traffic and traffic continuing straight ahead. Irish traffic lights use a combination of a full red light and a green directional arrow to express the fact that traffic moving in the direction of the arrow (whether turning or going straight ahead) may move, but traffic going in other directions may not.

I need pictures for this, but couldn’t find any online so these schema will have to do:
O red
–> green
means traffic turning right may go but traffic going straight ahead or left must stop.

This practice contrasts with New Zealand and the UK, for instance, which use a general go signal in combination with a red directional arrow prohibiting particular paths.
O green
<– red
(i.e. traffic turning left remain stationary, other traffic may go).

On the Irish system, when the traffic going straight-ahead may go but all turning traffic must stay stopped, you have a green arrow pointing straight ahead and a full red stop light.
O red
^ green

The system obviously works just fine in practice, but I don’t like it and here’s why the other system is better.

The Irish system gives inconsistent instructions to the driver whereas the other system gives discriminating advice. A full red stop light is a general injunction to stop. So when you see a red light and a green arrow, it is telling the traffic travelling in the direction of the arrow both to go (because of the arrow) and to stop because of the full red light. Since the red light is general it applies to the traffic going in the direction of the arrow as much as to other traffic. So the message is inconsistent. Go and don’t go.

The other system on the other hand is discriminating. A arrow of any colour is not general. It applies only to traffic going in the direction of the arrow, so a red directional arrow merely qualifies a full green go light. It says ‘Go (but not this way)’. The red arrow strikes off otherwise admissible paths. The message overall is consistent.

P.S. To those of you who say, ‘big deal, who cares?’ or ‘cough-autistic-cough’ I say, ‘harrumph. You probably also don’t care which way the toilet paper rolls off the roll. Off over the roll is obviously much better!’

Here’s a nice cartoon over at xkcd that speaks to the subject of this post.


11 thoughts on “Irish Traffic Lights

  1. ken

    How do you think a Green, Red, Amber system would work? Some cars would go through the red light just as it changes, as the ones who speed up on amber do now, but I expect people wouldn’t speed up on red like they do now on amber.

  2. Dot

    Come to think of it, you get
    0 red
    in the UK too – it’s called a filter arrow. The thing I don’t think I’ve seen in the UK is having an arrow that points straight ahead rather than left or right.

  3. What do you think of the marvelous sound effects – and their coincidence with the lights – on Irish pedestrian crossings? This is one of my favourite things about living here. I *still* have to stop myself from doing a little at-the-running-bl0cks then triumphant-dance routine. And the sounds vary, there are at least three different lots.

    Plus the pedestrian count-down – that is, the seconds until it goes green for you? Seen a lot in the States; fond of it myself. Essentially, anything that makes crossings more entertaining (the excitement of dodging traffic aside). And that encourages benign silliness in everyday life.

  4. Living in close proximity to a pedestrian crossing, the sounds have a certain surreal quality at 3.00 in the morning; however, a blind friend finds them very useful. I have yet to discover whether they have different sound sequences when there are crossings close to each other.

    Ken, The convention that a red light means “five more cars, please” would need to change if there were to be no amber. your point about inconsistent instructions is valid; there are similar problems with motorway signage. Overhead signs frequently suggest that the inside lane is only for traffic leaving at the next junction, causing drivers unfamiliar with the signage to pull out into the fast lane, only to discover that the lane from which they have moved continues as normal.

  5. Mick

    Absolutely fascinating. I thought at first that this was a “send-up” but I have have found food for thought reading through the various responses. The ambiguities indicated in the various red stop signs with associated green arrows reassures me that I am not as stupid as I thought; at least my confusion is shared at last.
    Next – how about Irish Roundabouts and car indicators…?

  6. ken

    @ Mick,
    No not a send-up, just a bit of OCD. RE: roundabouts. I’m afraid my own practice is a bit inconsistent. When I was back in New Zealand at Christmas, I noticed that Department of Transport or the Road Safety Authority, or the police, or someone in charge anyway had sent a post-card to everyone telling them the new way they want people to indicate: left for left, right then left as you go off for right, and nothing and then left as you go off for straight ahead. As a system that seems better than right and then left as you go off for straight ahead, which is the way I was taught, because that calls for a lot of switching indicators in a short space of time. The new instruction is crisper. I did like the fact everyone got a postcard, though. Very sensible.

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