Sensor Controlled Traffic Signals in Dublin

RacoonQueen · 26-04-2019 11:33pm

LPC786 wrote: »

I have noticed most the Traffic signals in Dublin are controlled by sensors. As soon as a vehicle comes in the range of the sensor it turns the signal to green and the vehicle can move. Thats why you will find most of the signals on green at night when there is less traffic

Where i live in tallaght there is a toad which says buses only. Sometimes after entering the lane most of the drivers realise they have entered a wrong lane and stop well short of the white line and not coming within the range of sensor. Consequently the signal remains red and it causes huge built up of cars behind. Its only after waiting for sometime in frustration or if someone from behind honks the horn that the front car moves a little and traffic starts flowing smoothly again. In order for a smooth flow of traffic RSA must start a guidance programme for drivers to at least reach up to the white line

They could also do with making some of them more cyclist friendly. Some of my bike routes have sensors and you literally have to cycle over the thin line of tar to get the sensor to change for you. Also, a lot of cyclists wouldn't know this. Have seen a light sequence HERE not change for a cyclist who was waiting as I approached. I cycled over the tar and told him what he needed to do to get the filter to come on and he looked at me like I was insane (I mean I am, but I was also right).
Some on quieter roads will change almost instantly when you cycle over them but again, if people don't drive they may not be aware of sensors so on quieter roads they could end up thinking their only option is to break the red.

AndrewJRenko · 26-04-2019 11:37pm

blackwhite wrote: »

S.30 of the 1997 Act

Relates to traffic lights where "traffic sign number RRM 017 [stop line]" is provided. In those cases, the traffic light indicates whether or not you are permitted to proceed past the line.
Once you are past the line, you proceed when safe to do so.

Do you mean the 1997 SI?

http://www.irishstatutebook.ie/eli/1997/si/182/made/en/print#article30
Where did you get the bolded bit from? Is this stated in the Act or SI?

Dravokivich wrote: »

I've been searching all morning and can't find the statement I mentioned earlier. But once you are within the junction, the lights no longer apply to you. My inability to find it again, doesn't mean it's not there. It's just a pain to find this stuff again when unfamiliar with referencing legal documentation.

Maybe, but if no-one here can find it, it's a fair indication that it doesn't exist.

blackwhite wrote: »

You need to go and read the RTAs and the rules of the road again.

A red light means that you cannot pass the light - or the line indicating the stop point where lines are provided. In cases of turning right, the car will have already passed the light or line when they move into the junction. If there is a light on the opposite side of the junction there is a requirement for a stop line to be marked on the side where the driver is supposed to stop. Once they've passed that line, they are supposed to then exit the junction once it's safe to do so.

ROTR is crystal clear. It says that you stop at a red light.

Where did you get the bolded bit from?

I'm actually talking about the 'straight on' scenario, rather than the right turn scenario. I've heard the excuse that 'the first light was amber' so it's OK to continue through the 2nd red. To me, that is pure BS.

I've never seen anything in legislation or ROTR to suggest that it's OK to drive through a red light.

ED E · 26-04-2019 11:56pm

Don't quote the ROTR Andrew. It's vague, sometimes wrong.

AndrewJRenko wrote: »

I've never seen anything in legislation or ROTR to suggest that it's OK to drive through a red light.

There is for amber

(2) A driver of a vehicle approaching traffic lights in which a non-flashing amber light is illuminated, shall not drive the vehicle past the traffic lights, or past traffic sign number RRM 017 (stop line) when such sign is provided in association with the traffic lights, save when the vehicle is so close to the traffic lights that it cannot safely be stopped before passing the traffic lights or traffic sign number RRM 017.

In the case of ahead of the red I think you'd not be considered to be controlled by that light if its only on "your" side of the junction but if doubled up I'm unsure.

AndrewJRenko · 28-04-2019 10:26am

ED E wrote: »

Don't quote the ROTR Andrew. It's vague, sometimes wrong.

There is for amber

In the case of ahead of the red I think you'd not be considered to be controlled by that light if its only on "your" side of the junction but if doubled up I'm unsure.

Yeah, I'm aware of the limitations of ROTR, and I know that RSA have put stuff in there that isn't in law from time to time, like their attempt to bring in mandatory use of cycle lanes.

Which is why I was looking for anything in law to say that it's OK to ignore the 2nd red light at a junction - but I've never seen anything that stands up this approach.

LeBash · 28-04-2019 10:40am

There are sensors placed in the road and when a car comes along, it completes the circuit then signals the traffic light controller and depending on the time of day, the time since changed and where you are it will change or start a timer.

That's the part to be careful about. Just because you see a square cut on the road, it doesn't mean you get immediate preference at night. The light may have been triggered and has a delay cycle to complete so your inching forward doesn't actually make a difference, or there is usually a road that doesn't get preference and it starts a delay on cycle.

You may think that it would be precise as to traffic volumes but it's usually a call made by the person installing the scats unit on the few hours they are there (or few mins they are looking, at least 15 years ago, that was the case). They do get looked at after though especially if people get in touch with the council.

The cyclist who was on at the start of the thread, it "should" trigger for you also. Perhaps try approach a little more centred in the lane if traffic allows. It's not the weight of the vehicle, that should trigger it, it's being picked up by a microwave. This may all have change in the last 15 years but I've seen installs and keep my eye on them, they look the same parts.

blackwhite · 28-04-2019 11:38am

AndrewJRenko wrote: »

Yeah, I'm aware of the limitations of ROTR, and I know that RSA have put stuff in there that isn't in law from time to time, like their attempt to bring in mandatory use of cycle lanes.

Which is why I was looking for anything in law to say that it's OK to ignore the 2nd red light at a junction - but I've never seen anything that stands up this approach.

It’s been pointed out to you exactly where the legislation allows for this.
It’s where there’s a light with a line also provided. In those cases you stop at the line, or the light.

If there’s a 2nd light on the opposite side of the junction, the stop line remains the same, and it’s the colour of the lights when you are approaching/passing the line that becomes relevant, not when passing the lights themselves.

As an example - when coming down Drummartin Road there’s a cross roads at the Goat. There’s a filter light for traffic coming from Sandyford to turn left towards Dundrum that turns green whenever the primary sequence is giving a green for Taney Rd traffic.

Every now and again you see an idiot who turns the corner, and then spots the red for traffic from Mount Merrion, and stops on the corner. If you think this kind of behaviour is correct then, to be honest, you shouldn’t be anywhere near the road.

AndrewJRenko · 28-04-2019 12:08pm

LeBash wrote: »

installing the scats unit

Really? Did no-one tell them? You'd have to wonder what you'd have to do to activate that unit.

LeBash wrote: »

The cyclist who was on at the start of the thread, it "should" trigger for you also. Perhaps try approach a little more centred in the lane if traffic allows. It's not the weight of the vehicle, that should trigger it, it's being picked up by a microwave. This may all have change in the last 15 years but I've seen installs and keep my eye on them, they look the same parts.

There are definitely junctions that don't trigger for cyclists. I've seen many cyclists mention St Stephen's Green, heading onto Earlsfort Terrace. I'm fairly sure that Birches Lane onto Taney Road doesn't trigger for a cyclist either.

blackwhite wrote: »

It’s been pointed out to you exactly where the legislation allows for this.
It’s where there’s a light with a line also provided. In those cases you stop at the line, or the light.

If there’s a 2nd light on the opposite side of the junction, the stop line remains the same, and it’s the colour of the lights when you are approaching/passing the line that becomes relevant, not when passing the lights themselves.

As an example - when coming down Drummartin Road there’s a cross roads at the Goat. There’s a filter light for traffic coming from Sandyford to turn left towards Dundrum that turns green whenever the primary sequence is giving a green for Taney Rd traffic.

Every now and again you see an idiot who turns the corner, and then spots the red for traffic from Mount Merrion, and stops on the corner. If you think this kind of behaviour is correct then, to be honest, you shouldn’t be anywhere near the road.

Yes, I've seen those situations when turning left or right. I see it occasionally with traffic turning right from Marlborough Road onto Sandford Road, who freeze when they come round to the red light.

The situation I'm querying now relates to traffic heading straight, not turning right. I've heard people use the excuse that, once you manage to get through the first light at a junction on green or amber, you're OK to go through the second light which is by then red. I don't believe that this is right. It's just an excuse for amber gambling. If you see a red that applies to you (as opposed to one intended for traffic coming from a different direction), you need to stop. You need to plan your entry to the junction with this in mind, to avoid getting 'stuck' in the junction.

I'm looking for anything in law to confirm or deny my view on this.

railer201 · 28-04-2019 1:48pm

For clarity concerning lights controlled by induction loops :-

These are visible on the ground as a rectangle or a series of rectangles, and it is the sides of the rectangle in the direction of travel that is being referred to.

As has been mentioned in a few posts above including mine, if one cycles directly along/over one of the side strips then the light sequence will trigger, not necessarily immediately though.

It has nothing to do with the weight of the bike, more presenting enough metal close to the sensing loop, so the sequence will trigger.

Some may act immediately, others are delayed but I've yet to come across one that doesn't react to running my wheels along the strip.

AndrewJRenko · 28-04-2019 2:17pm

railer201 wrote: »

For clarity concerning lights controlled by induction loops :-

These are visible on the ground as a rectangle or a series of rectangles, and it is the sides of the rectangle in the direction of travel that is being referred to.

As has been mentioned in a few posts above including mine, if one cycles directly along/over one of the side strips then the light sequence will trigger, not necessarily immediately though.

It has nothing to do with the weight of the bike, more presenting enough metal close to the sensing loop, so the sequence will trigger.

Some may act immediately, others are delayed but I've yet to come across one that doesn't react to running my wheels along the strip.

I'm far from being the only one who has experienced the problem at Earlsfort Terrace. If they don't work for lots of people, they don't work.

https://twitter.com/KarlaHealion/status/626781548092764160
https://twitter.com/portixol/status/626462388171239424
https://twitter.com/2011ireland/status/717279261082693632

railer201 · 28-04-2019 3:01pm

AndrewJRenko wrote: »

I'm far from being the only one who has experienced the problem at Earlsfort Terrace. If they don't work for lots of people, they don't work.

You don't say whether these lights are controlled by induction strips or not ???

If they are - you don't say whether you've run your wheels directly along one of the 'strips' I've referred to ???

Lots of lights won't work for people who don't know the basics of how to trigger them - whether they're on two wheels or four.

AndrewJRenko · 28-04-2019 3:04pm

railer201 wrote: »

You don't say whether these lights are controlled by induction strips or not ???

If they are - you don't say whether you've run your wheels directly along one of the 'strips' I've referred to ???

Lots of lights won't work for people who don't know the basics of how to trigger them - whether they're on two wheels or four.

I've no idea whether the lights are controlled by induction strips or not. I didn't think that traffic lights needed special instructions about special things to do to get through them. You can be sure that they wouldn't implement something that needed drivers to run their wheels directly along strips to work.

Victor · 28-04-2019 3:38pm

blackwhite wrote: »

As an example - when coming down Drummartin Road there’s a cross roads at the Goat. There’s a filter light for traffic coming from Sandyford to turn left towards Dundrum that turns green whenever the primary sequence is giving a green for Taney Rd traffic.

Every now and again you see an idiot who turns the corner, and then spots the red for traffic from Mount Merrion, and stops on the corner. If you think this kind of behaviour is correct then, to be honest, you shouldn’t be anywhere near the road.

Those llights need to be fitted with blinkers, so that flow of traffic can't see the lights.

https://www.google.com/maps/@53.2927517,-6.2294862,3a,75y,286.4h,79.43t/data=!3m5!1e1!3m3!1s9fUp-78PV4vGhsBRef4IoQ!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3D9fUp-78PV4vGhsBRef4IoQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D18.76217%26pitch%3D0%26thumbfov%3D100

railer201 wrote: »

You don't say whether these lights are controlled by induction strips or not ???

There appears to be something, but it's non-standard: https://www.google.com/maps/@53.3363591,-6.2571747,3a,31y,92.94h,63.21t/data=!3m6!1e1!3m4!1s1AfCVwuu1ciZ2VMUC33zQg!2e0!7i16384!8i8192

railer201 · 28-04-2019 3:44pm

AndrewJRenko wrote: »

I've no idea whether the lights are controlled by induction strips or not. I didn't think that traffic lights needed special instructions about special things to do to get through them. You can be sure that they wouldn't implement something that needed drivers to run their wheels directly along strips to work.

No indeed, but drivers do have to position their cars within the induction loop for the lights to trigger, otherwise they'll be there for ever and a day - it happens quite often. Drivers also fail many times to position themselves on the smaller induction loops in the centre of junctions and fail to get the green right turn arrow as a result.

There's something for the cycling associations to bring up with the relevant authorities - alter the induction loop sensitivity to pick up cyclists anywhere within the induction loop, similar to cars, buses etc..

blackwhite · 28-04-2019 4:41pm

AndrewJRenko wrote: »

Really? Did no-one tell them? You'd have to wonder what you'd have to do to activate that unit.

There are definitely junctions that don't trigger for cyclists. I've seen many cyclists mention St Stephen's Green, heading onto Earlsfort Terrace. I'm fairly sure that Birches Lane onto Taney Road doesn't trigger for a cyclist either.

Yes, I've seen those situations when turning left or right. I see it occasionally with traffic turning right from Marlborough Road onto Sandford Road, who freeze when they come round to the red light.

The situation I'm querying now relates to traffic heading straight, not turning right. I've heard people use the excuse that, once you manage to get through the first light at a junction on green or amber, you're OK to go through the second light which is by then red. I don't believe that this is right. It's just an excuse for amber gambling. If you see a red that applies to you (as opposed to one intended for traffic coming from a different direction), you need to stop. You need to plan your entry to the junction with this in mind, to avoid getting 'stuck' in the junction.

I'm looking for anything in law to confirm or deny my view on this.

It’s been shown more than once. Lights which have a second light on the far side of the junction will also have a stop line. In those situations the lights are an instruction to stop at the line - not the lights.
If you have passed the line whilst the light is on green then you must continue and exit the junction.
You aren’t supposed to enter the junction to begin with if it isn’t clear to exit. (unless turning right)

The law is the same whether going straight in or turning - the lights on the opposite side indicate whether or not to stop at the line - not at the lights themselves. It was laid out in the original 1963 Act, and again in the 1997 SI.

Once the stop line is present then the traffic light mean stop at the line - not the lights.

railer201 · 28-04-2019 6:45pm

Victor wrote: »

There appears to be something, but it's non-standard: https://www.google.com/maps/@53.3363591,-6.2571747,3a,31y,92.94h,63.21t/data=!3m6!1e1!3m4!1s1AfCVwuu1ciZ2VMUC33zQg!2e0!7i16384!8i8192

https://www.bikewalknc.org/bicycle-detection-at-traffic-signals/

Figure 4 seems to show this type of diagonally arranged inductive loop which is specifically for bicycles.

AndrewJRenko · 28-04-2019 9:00pm

blackwhite wrote: »

It’s been shown more than once. Lights which have a second light on the far side of the junction will also have a stop line. In those situations the lights are an instruction to stop at the line - not the lights.
If you have passed the line whilst the light is on green then you must continue and exit the junction.
You aren’t supposed to enter the junction to begin with if it isn’t clear to exit. (unless turning right)

The law is the same whether going straight in or turning - the lights on the opposite side indicate whether or not to stop at the line - not at the lights themselves. It was laid out in the original 1963 Act, and again in the 1997 SI.

Once the stop line is present then the traffic light mean stop at the line - not the lights.

The distinction between stopping at the light or stopping at the line is a bit of a moot point, seeing as they are largely adjacent to each other.

Are you saying if you were foolish enough to pass the first light/line on a late amber, and the second light goes red before you reach it, you then have to stop in the middle of the junction, before the 2nd light/line?

blackwhite · 28-04-2019 10:57pm

AndrewJRenko wrote: »

The distinction between stopping at the light or stopping at the line is a bit of a moot point, seeing as they are largely adjacent to each other.

Are you saying if you were foolish enough to pass the first light/line on a late amber, and the second light goes red before you reach it, you then have to stop in the middle of the junction, before the 2nd light/line?

The 2nd light (normally on the opposite side of the road) doesn’t have a 2nd stop line. Both lights are linked to the first stop line before someone enters the junction.

Both first and second lights change simultaneously. Once they change to orange, any vehicle before the line has to stop if safe, and any car past the line should continue and exit the junction.

IMO it’s highly unlikely that anyone would enter legally on orange and not have cleared the junction before the lights turn red, without the lights having turned orange early enough for them to have stopped safely at the line (unless of course they are legally turning right).

But either way - you seem to be continually shifting the goalposts and ignoring anything that doesn’t fit into whatever narrative you built in your head for your latest crusade

Sensor Controlled Traffic Signals in Dublin

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