Stop! - Redlight

[mpwilson99]

Hi All,

On my way home tonight, I had that situation at the traffic lights (with a redlight camera), where you say to yourself if the lights change now your at that point of no return and must cross the junction, either that your going to slam on the brakes and then be sitting in the middle of the crossing box!

Well, im hoping that im going to be ok, but it could be a tad touch and go, but im wondering does anyone know exactly how these cameras work, how much allowance there is, whats the trigger point etc in the camera flashing etc..

As it was daylight i didnt see any flash, and im probably ok, but i have always wondered about the tolorances of these cameras.

BTW - I was definately not speeding across the lights either, only in the gentle flow of traffic, which makes me worry even more!

Cheers

MPW

[GPS_fan]

As I recall, these cameras work by means of an induction loop in the road surface close to the white line and when the traffic light changes to red, this induction loop is activated.

You might find a more detailed explanation here

By the way, is this redlight included in the database? If not, have you added it?
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Andy
PocketGPSWorld.com supports Help for Heroes - Read here

[mpwilson99]

Hi, thanks for that link.

It is one in the database, and admittedly i should know better!

But when the lights do change against you and right on top of you, and you have other cars up your chuff then its not as simple as it sounds.

From reading the `how it works` page, i would say i would be safe, as i probably was over the first induction loop on the amber light .( just ).

I would be interested to know what the UK `grace period` was before these loops are activated after the lights change red.

Is it still two weeks before I can stop sweating?

Still, i think ive also just learnt something else here, looking at the photo on that site on what the loops look like, they also look like alot of other marks on the road i see, generally around traffic lights, barriers, etc....
Are these induction loops also used to check on traffic approaching traffic lights to get them changed to/for your direction? is it better to go over these particualr loops quick or slow to get the lights to change? - Is my old traditional method of getting the lights to change by flashing at them just in my imagination?

Cheers

MPW

[DennisN]

The loops detect your vehicle passing over them (I recall some years ago coming up against a set of lights which refused to change until I reversed and sat the car on top of the loops! When I went through the same set on a moped, the things never ever changed!!) There's a set of lights in Street (Somerset), which are perfectly set up - if there's no traffic about, you approach them at the speed limit (40mph) and they'll change as soon as you cross the diamond shaped loops and are green well before you get to them (fine at the dead of 4am, but not reliable at 4pm!!).

I've just been reading about this and from memory, the flash is half a second after they turn red, before which you get 3 seconds of Amber.

ACPO says at 40mph, stopping distance is 36.5 metres, whereas distance travelled in 3 seconds is 53.6 metres. I'm a mathematical dumbo, but I think what that means is that you should not be there when the flash goes off - i.e. either you had time/distance to stop for the Amber, or you had gone well beyond the crossing before you got flashed. Am I right anybody?

This is not a moral judgement - my only ever points in 45 years were for this. Not a camera, but a PC in a car, who saw a white van and did me. He maintained the crossing traffic had 2 seconds of green before I went through the lights, which wasn't true at all, but I was a whitevanman and didn't know the above at the time and who'd be believed in court?, so I took the £60 and 3 points (long since expired now).
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Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!

[mpwilson99]

[Darren]

Many possible uses, traffic census or possible the old DS2 speed measurement. In DS2 the loops are buried in the road scamera vans and other sues can then plug in to the system. Normally used in conjunction with a camera van.
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Darren Griffin

[Foci]

The same thing happened to me at the end of a 60 mph stretch of road, where the stop line was further back than i expected, because of bright winter sun and worn off white line i overshot the line by a metre or so and ended up with 3 points even though i did not go over any box junction or crossing, i was told if both sets of wheels go over thats it.

[Darren]

But it must have been more than a metre over the line if both wheels had crossed?
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Darren Griffin

[Foci]

I still dont think both sets of wheels crossed, and i did not see the flash so did not pay much attention, first i knew was when NIP came through a week later, but was told when i phoned Devon and Cornwall safety cam partnership that it must have been the case.

It was in Newton Abbot and i was told by a friend that due to worn off road markings it happens all the time, probably a good earner as it catches out the holiday traffic who dont know the area.

[Darren]

Did you have our database running at the time? Was it one of the red light cameras we have recorded in Newton Abbot?
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Darren Griffin

[Foci]

It was before i had my TT, in fact after months of putting off getting one i went out and got my sat nav the following day after i recieved the fine ! and discovered the PGPSW database shortly after.

and yes it is recorded in the database.

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