Gatso cameras - work both ways at the same time?

[jonboy]

Does anyone know if the roadside speed cameras (just the standard yellow box on a pole type) can be set to catch people in both directions without being adjusted in between?
Reason I ask is that I passed one on the way home from work at 10pm with 32mph on the clock and got flashed ( a picture of my rear plate). Now I thought with an indicated speed of 32, i'd probably be doing a real 30/31 maximum, and wouldn't be caught.
The next morning I saw the camera flash someone going in the opposite direction (ie it photoraphed their front plate). It seems unlikely anyone adjusted it overnight, so maybe when it seemed to flash me it was actually someone catching someone going the other way? Or, are the cameras capable of watching the traffic going in both directions at the same time?

[carvell]

They only photograph the rear of vehicles.

However, they have been known to accidently photograph cars coming the other way, this can not and will not be used as evidence for a speeding conviction, they'll just ignore the pictures.
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Yamaha TDM 850

[stinkwheel]

Yeah, they use a doppler radar to check the speed of the car which then triggers the camera to flash. The doppler measures speed as opposed to velocity. If you remember your physics from school, this means it cannot tell which direction you are going in only how fast.

Therefore it flashes vehicles in both directions but only the ones it photographs from behind will be issued tickets. The ones pictured from the front are beyond the camera by the second flash.

Newer Gatsos seem to be able to differentiate direction, the ones on the A9 certainly do because I deliberatley went through two of them at over the ton head-on to check and neither of them flashed.
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[jonboy]

Well this seems like bad news as it would be me that got flashed then. I would feel a bit unlucky though with 32 on the clock as with speedo error this would be barely if at all over the limit.

[JonB]

Watched an interesting program on M & M last night, only 1 in 4 flashed drivers from Gatso's actually get issued with a ticket apparantly.

The only cameras that flash you from the front are the Truvelo's, I've never seen a Truvelo, but they look like Gatso's, but they have a red and purple lens next to each other and they tend to be blue in colour. There are about 300 in the country.
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Be careful whose advice you buy, but, be patient with those who supply it. Advice is a form of nostalgia, dispensing it is a way of fishing the past from the disposal, wiping it off, painting over the ugly parts and recycling it for more than it?s worth.

[jonboy]

/me lives in hope.

[carvell]

[JonB]

Apparantly that's a hidden myth as well, the presenter said that there is a misconception that it is infrared, but in fact there is a red and purple lens to blank out a flash so that it does not blind the oncoming driver.
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Be careful whose advice you buy, but, be patient with those who supply it. Advice is a form of nostalgia, dispensing it is a way of fishing the past from the disposal, wiping it off, painting over the ugly parts and recycling it for more than it?s worth.

[Zero-G]

I've been flashed by the same Truvelo 6 times before in Chesterfield.

The flash is a blue colour insted of just a white flash. Dont know if it is designed to be less blinding or it is that colour for some other purpose. However it is less blinding than the normal white ones.

[carvell]

[zaknafien]

I've been flashed by a front facing camera. Anyone who wishes to argue can come up to mine and i'll show you the camera that does it.
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02 Firestorm.

[carvell]

The filter had probably fallen off/was taken off.
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Yamaha TDM 850

[Mr C]

I was definitley flashed by a Gatso (not Truvelo) on the A68 just over Carterbar on the Northbound side of the road when I was travelling south.

Took me by surprise so I went and did it again
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187.3bhp = 201mph

[Phoenix]

Jonboy they do flash oncoming cars, as I got flashed heading towards a camera in a 40 at about 50 which was facing me on the opposite side of the dual carriageway, not recieved a ticket for it.

Did you get a single flash? Some cameras flash once to warn if u're going slightly too fast I believe, only a double flash for breaking the ticket speed limit. Or it was indeed an oncoming car, or one behind you going too fast, can't see a 30 camera going off at 32.

[jonboy]

Definitely a double flash, and I was deffo only doing 32. Why the double flash anyway - is it a time delay thing so they have photo proof of how far you went between the flashes which then tells you the speed?

[carvell]

It takes two photos, these are a certain time apart, they know the time between pictures, they know the distance your car went in this time (marks on the road) therefore they can work out your speed manually should they need to.
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Yamaha TDM 850

[Davo]

Was there another vehicle going the other way? If so it may have triggered the Gatso.

[tgabber]

[cliff]

There is one at the bottom of my road that flashes me from the front every time. But I've got no numberplate on the front, so I don't care!
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[Ninja]

[Mr C]

but wrong

since the doppler effect has the effect of either compressing or stretching the reflected waves (blue shift or red shift) it can indeed sense direction

this is why an exhaust note changes as it comes toward you then away from you

the frequency changes
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187.3bhp = 201mph

[8316]

[stinkwheel]

[Mr C]

aha OK thanks

I suspected it must be something like that

I only just ventured beyond Carterbar last time but I do seem to remember that the A68 further north is littered with the bastard things
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187.3bhp = 201mph

[mamak]

In South Africa we have three methods. The oldest is with a set of wires laid across the road surface or embedded in the surface with fixed cameras. We also have the radar and the latest mobile ones are laser. Ours are still painted grey. The fixed cameras both using wires and radar are positioned to get your rear numberplate for the sole reason that other cars on your side of the road should not see the flash thus enabling them to slow down and avoid getting caught. They are usually in the middle island between bushes. The laser ones are harder to spot as they look like video cameras on tripods and can be very cleverly positioned. However our Metro Police in Johannesburg uses the same locations and at the same times so most locals know where to slow down. They take multiple shots with a single flash to ensure the correct vehicle is being photographed.
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sliding by the seat of my pants. OUCH!!!