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Can you get caught driving over the limit TOWARDS a Gatso?

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Steve

Post subject:

Posted: Thu Apr 19, 2007 19:33

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SafeSpeed wrote:

The detection method is to sum the send and return radar signals. The difference frequency is in the audio range and the speed is calculated from this audio frequency.

The vibrating panel does not do doppler but modulates the return signal which gives rise to a spurious audio frequency signal. The audio frequency passes through the filter and gets measured.

Ah! I'm with you. That makes perfect sense. Cheers Paul 8-)

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crE

Post subject:

Posted: Wed Apr 25, 2007 16:52

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Joined: Wed Apr 18, 2007 17:25
Posts: 7

Strange...

Hi there, (I'm the guy who orignally posted the question)..

I was driving past the same camera today, in the exact same situation as before. I thought I'd go at 40mph-45mph to see if the last time was a fluke, or whether the camera DID flash if I was going over the limit.. (Yes I did make sure it was safe to do so!)

Lowe and behold, the bloody thing flashed again!! I'm pretty sure by the second flash I was almost at a right angle with the camera.. Now I don't know how wide a lense these things have??

I'm getting slightly paranoid about this now!

Nick

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Ziltro

Post subject:

Posted: Wed Apr 25, 2007 17:06

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Joined: Thu Jun 23, 2005 02:50
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Location: Dorset

Have a good look in the top left 'hole' and see if you can see a lens.

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botach

Post subject:

Posted: Wed Apr 25, 2007 19:05

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Joined: Fri Sep 24, 2004 23:26
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Location: Treacletown ( just north of M6 J3),A MILE OR TWO PAST BEDROCK

Just wondering how effective complaining to the police about an "unsafe" camera might be . I got flashed in the face by one locally and reported it( it was a Gatso) - even got a call back to tell me that the technician had responded. Now if enough cameras got reported would we have overworked camera technicians, possibly leading no spare parts :wink:

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hairyben

Post subject:

Posted: Wed Apr 25, 2007 22:30

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Joined: Sun Sep 25, 2005 15:00
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if gatso's got people going in the opposite direction I'd have about 1000 points on my licence. there were 4 on the A48 in gloucs i passed on a daily basis in the late 90's-early 00's and made it my mission to waste as much of their film as possible...

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crE

Post subject:

Posted: Sun May 20, 2007 15:00

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Joined: Wed Apr 18, 2007 17:25
Posts: 7

This is a definate...

I was driving 35mph+ towards a camera again today. And it flashed, and I made sure there was no other cars travelling in the other direction that it could have been..

Why did it flash? I thought it could not catch you going in that direction?

Is it a case of they cant prosecute you? Or is it technically impossible for it do calculate your speed?

Getting a little restless now!!

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crE

Post subject:

Posted: Sun May 20, 2007 15:06

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Joined: Wed Apr 18, 2007 17:25
Posts: 7

I think I may have answered my own question...

Quote:

GATSO – Fixed Roadside

Uses Radar to measure vehicle speed. Takes two photographs of the rear of the vehicle, white lines painted after the camera are used as secondary checks to ensure that the correct speed was measured. Depending on vehicle speed depends on how many white lines have been passed and a comparison is made between the two photographs. Can only be used to photograph from the rear and can only enforce in one direction, unless the camera is sited in the middle of the road, which means the camera housing can be turned round. Some police forces paint lines on both sides of the road to give the impression that it can be used for enforcement on the opposite carriageway.

REF: http://www.blackspot.com/support/camera_info.htm

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patdavies

Post subject:

Posted: Mon May 21, 2007 11:29

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Joined: Wed Jan 12, 2005 16:37
Posts: 265

The important thing is not the technical capability of the camera at all.

GATSO (but note, not all cameras) are only Type-Approved by the Home Office for receding traffic.

Even if the SCP could calculate your speed in approaching mode, you cannot be prosecuted for it. The lack of Type-Approval renders it impossible to issue a S.20 statement and thus there can be no evidence of speed. Even if they dispensed with the S.20 certificate and got an SCP employee to the court as a witness, again the lack of type approval makes any reading from the camera opinion rather than evidence which would not reach the standard of beyond reasonable doubt.

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ElandGone

Post subject:

Posted: Mon Jun 04, 2007 13:52

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Joined: Mon Jun 04, 2007 13:15
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crE wrote:

peeps forget that Gatso's can be used to police EITHER side of the road...but NOT BOTH at the same time...that's why you see markings on both sides of the road and only one camera.

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Steve

Post subject:

Posted: Mon Jun 04, 2007 15:07

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Joined: Sun Sep 25, 2005 10:16
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Location: Moved to London

ElandGone wrote:

peeps forget that Gatso's can be used to police EITHER side of the road...but NOT BOTH at the same time...that's why you see markings on both sides of the road and only one camera.

An example of:

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jomukuk

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Posted: Mon Jun 04, 2007 20:12

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Joined: Sun Sep 03, 2006 04:10
Posts: 3244

So, what is this camera looking at?
And why does it "flash" at vehicles going EITHER way ?
You can see the shadow of the camera unit and the TWO sets of bars EACH side of the road. I've watched it "flash" an astra going right to left and then two ducatis going left to right. The village is yardley hasting, A428 northants.

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Steve

Post subject:

Posted: Mon Jun 04, 2007 21:01

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jomukuk wrote:

I was about to post:

You can tell from the bars that the camera is a Truvelo (unlike the photo I gave which showed a Gatso). The speed sensor is based on a set of pressure strips, permanently buried underneath the road surface. In this case there are 4 sets. The camera (between the carriageways) is on a swing arm which allows it to be pointed at one of the 4 sets of white lines. The camera can't simultaneously photograph two or more areas, but the speed sensors and the flash can still put the willies up those who are above the trigger speed (as determined by the still active sensors) but who are not in view of the camera (without necessarily wasting film).

But then I noticed the camera is at the side of the road as opposed to between the carriageways as I had described (I have the latter type of Truvelo setup near me). In your case the camera could well be monitoring either lane but you couldn't tell which. They are approved for both front and rear evidence capture. Again it could be triggering the flash to put the willies up those above the threashold; however, I don’t know of any reason why that speed camera could not provide approved evidence from both lanes simultaneously.

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botach

Post subject:

Posted: Mon Jun 04, 2007 21:29

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Location: Treacletown ( just north of M6 J3),A MILE OR TWO PAST BEDROCK

ElandGone wrote:

peeps forget that Gatso's can be used to police EITHER side of the road...but NOT BOTH at the same time...that's why you see markings on both sides of the road and only one camera.

Can someone advise or correct on this -

Thought due to type approval Gatso only approved for rear facing detection.
Truvello only type that has type approval for either direction ,and in forward direction uses three strips ,then three white lines, in rear-ward set up uses same markings as Gatso.

Main reason quoted was due to flash arrangement.

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

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ElandGone

Post subject:

Posted: Tue Jun 05, 2007 14:25

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Joined: Mon Jun 04, 2007 13:15
Posts: 135

botach wrote:

ElandGone wrote:

peeps forget that Gatso's can be used to police EITHER side of the road...but NOT BOTH at the same time...that's why you see markings on both sides of the road and only one camera.

Can someone advise or correct on this -

Thought due to type approval Gatso only approved for rear facing detection.

Indeed, and if the camera is turned to police the opposite lane it is again taking rearward pictures...is it not?:wink:

Quote:

Truvello only type that has type approval for either direction ,and in forward direction uses three strips ,then three white lines, in rear-ward set up uses same markings as Gatso.

Main reason quoted was due to flash arrangement.

The 'Flash' on a Truvelo is infra red you can't see it and so poses no danger to motorists if it 'snaps' a full frontal view of ya attaining escape velocity. :wink:

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cabbie

Post subject:

Posted: Tue Jun 05, 2007 14:39

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Joined: Wed Jun 28, 2006 04:11
Posts: 171
Location: South East

Botach wrote:

ElandGone wrote:

peeps forget that Gatso's can be used to police EITHER side of the road...but NOT BOTH at the same time...that's why you see markings on both sides of the road and only one camera.

Can someone advise or correct on this -

A gatso can only be used to cover both directions if it is mounted on a central reservation - in other words, it cannot be used accross an approaching lane to monitor the receeding one

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Steve

Post subject:

Posted: Tue Jun 05, 2007 14:48

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Joined: Sun Sep 25, 2005 10:16
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Location: Moved to London

ElandGone wrote:

The 'Flash' on a Truvelo is infra red you can't see it and so poses no danger to motorists if it 'snaps' a full frontal view of ya attaining escape velocity. :wink:

To date this is wrong (but is just about to change).
The common UK truvelo known as the Combi SMC uses a magenta filter remove the green portion of the flash, hence the flash appears pink - very visibly so. I know because we have many of these buggers around Portsmouth and they do a roaring trade.

Only the new style truvelo might make use of an IR flash.

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toonbarmy

Post subject:

Posted: Tue Jun 05, 2007 18:14

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Joined: Wed Jun 14, 2006 17:20
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if the Gatso did not have a camera housing installed, but just the Radar unit the it would probably flash oncoming traffic, but seeing as there is no camera unit in there, you could not be identified

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Ziltro

Post subject:

Posted: Thu Jun 07, 2007 04:28

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Joined: Thu Jun 23, 2005 02:50
Posts: 2868
Location: Dorset

jomukuk wrote:

I would guess that it is reversible to look at either side and the lines on both sides would be so that you can't bypass the sensors by simply going on to the other side of the road.

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patdavies

Post subject:

Posted: Thu Jun 07, 2007 11:41

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Joined: Wed Jan 12, 2005 16:37
Posts: 265

botach wrote:

That is my understanding also. In rear facing operation the Truvelo is used in identical mode to a Gatso and thus should have the 'Gatso' lines. In forward facing mode, the secondary check is that the vehicle wheels are n the white lines.

Simply, a Truvelo operates in different modes depending on which way it is facing.

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Ziltro

Post subject:

Posted: Fri Jun 08, 2007 02:59

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Joined: Thu Jun 23, 2005 02:50
Posts: 2868
Location: Dorset

patdavies wrote:

Gatso 24 thang uses radar, Truvelo Combi SMc uses road sensors. They can't operate in the same way. I don't know why the Truvelo can't have rear facing mode working the same as front facing. I'd like to know though.

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