Flashing green

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Craig91
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Flashing green

Post by Craig91 »

Has anyone ever seen a flashing green light ahead of an amber in Britain before? I was travelling today through the junction of Great Queen Street and Kingsway, near Holborn, and a set of temporary lights did just that. I wonder if they were on a “European” setting or whether this is some sort of trial.

I’ll try and take a video next time I’m around there.
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traffic-light-man
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Re: Flashing green

Post by traffic-light-man »

I very much doubt it would be a trial.

Were they portable signals (the little battery powered units) or temporary signals (i.e., normal signals in a temporary foundation)?

I imagine there's room in both sectors for European sequences to make an appearance, but they certainly shouldn't. Then again, they're TTM signals either way, so it's no surprise :roll:
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Craig91
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Re: Flashing green

Post by Craig91 »

traffic-light-man wrote: Fri Apr 16, 2021 05:23 I very much doubt it would be a trial.

Were they portable signals (the little battery powered units) or temporary signals (i.e., normal signals in a temporary foundation)?

I imagine there's room in both sectors for European sequences to make an appearance, but they certainly shouldn't. Then again, they're TTM signals either way, so it's no surprise :roll:
Yeah they were portable signals. Must be a mistake.
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rhyds
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Re: Flashing green

Post by rhyds »

Was the flashing a slow, regular type of flash (as you get on LED pedestrian ambers) or a rapid flashing? Its possible that the green LED array has a fault that causes it to cycle on and off (for example a failed capacitor or an LED element that cuts in and out)
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Craig91
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Re: Flashing green

Post by Craig91 »

It definitely didn’t feel like a fault. It was a regular green flash just before it changed to amber, just like you get in some European countries.
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KeithW
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Re: Flashing green

Post by KeithW »

I have never seen this in the UK but have seen it in the USA. On some divided highway state roads with light controlled junctions the green lights will start flashing to warn drivers they are about to see an amber, in Canada they do something similar with pedestrian crossings, a flashing green warns drivers that a pedestrian could press the button and turn the lights to amber then red.
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traffic-light-man
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Re: Flashing green

Post by traffic-light-man »

Canada use two types of flashing green, they have a 'rapid' flash, which signifies an exclusive movement, and then a regular flash which signifies a pedestrian crossing as mentioned. Of course that's not applied in every province, it's a bit of a pick-and-mix.

Never heard of a flashing green in advance of yellow being used in the United States, though.

Massachusetts previously had an unusual standard for pedestrian crossings sited at crossroads, whereby the main road would flash green (like the Canadian crossings) and the side road would flash red, but with the flashing red being in the lower aspect of the signal head as a substitute for green. When a pedestrian pressed the button, all the signals would change to yellow, then red and the red and yellow would illuminate together to signify that the pedestrians had a exclusive stage in which to cross. The signals then returned to their flashing state. The controller would quite simply be one phase, with all the signals wired to that one phase, cycling to red and yellow only when a button was pressed.

I believe that the very few remaining installations of this type are legacy will be replaced (eventually) with a more standard set up.
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Chris Bertram
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Re: Flashing green

Post by Chris Bertram »

KeithW wrote: Sun Apr 18, 2021 10:26 I have never seen this in the UK but have seen it in the USA. On some divided highway state roads with light controlled junctions the green lights will start flashing to warn drivers they are about to see an amber, in Canada they do something similar with pedestrian crossings, a flashing green warns drivers that a pedestrian could press the button and turn the lights to amber then red.
Have seen this in Vancouver, so I presume it applies to BC. It appears to be the "steady state" for ped crossings, which are normally situated at road crossings anyway, given the grid-plan design of the streets in transatlantic cities.,
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Gareth
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Re: Flashing green

Post by Gareth »

In British Columbia, flashing green is used where a pedestrian crossing is on a main road where it intersects with a small side road. The side road has no signals but rather STOP signs. The flashing green tells you that although pedestrians have a DON'T WALK, vehicle traffic may still come out of the side road. You have priority but must still pay attention.

In Ontario and other parts of Canada, as Simon says, flashing green means that oncoming traffic has a red light. I think it's falling out of favour though with a solid green ball and arrow starting to get more popular.

I never knew flashing green had ever been done in the United States. It's certainly not allowed these days.
WhiteBlueRed
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Re: Flashing green

Post by WhiteBlueRed »

Here in Russia, and later in most ex-Soviet countries, since the early 2000s, modern traffic lights flash the green light 3 times before it changes to amber. It's not required by our GOST, but it is recommended.
It's likely that the temporary traffic lights were running on an Eastern European controller.
Pedestrian signals also flash the green man atleast 3 times before changing to a red man.
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