Which devices can the police legally use?
After a 1999 Scottish case where the police failed to make a prosecution stick when they implied that using the PolicePilot must be legal "because they'd been using it for years", here's a table of what the police can actually use legally. Simply put, if it's not a home office type-approved device, the police cannot use it to secure a conviction against you.With one exception: VASCAR and PolicePilot come under the heading of distance-over-time measuring devices, and these types are exempt from Home Office Type Approval. So don't try to use that Scottish case as an example in England - it won't work.

We have a new page to give advice on how you may avoid your speeding penalty click here.

Once you have had a look at the technology they can use listed below, then read the Rules that they should follow when they are using them - see Speed Trap useage rules law

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This table is correct and valid as of July 2010. A general Home office link to speed measuring devices can be found here. We believe that none of the tests that are conducted with each new Police device is ever tested against a motorcycle and that this is being used in at least one case to try and disprove the accuracy of the claimed speed.

Device Type Restrictions / usage Manufacturer Distributor Type Approval/Renewal Date
SVDD n/a Symonds Group Ltd Speedcheck 01-Apr-99
Riegl LR90-235/P n/a Riegl Laser Measurement System GmbH Jenoptic UK 16-Oct-98
Riegl FG21-P n/a Riegl Laser Measurement System GmbH Jenoptic UK 15-Oct-99
Laserpatrol SpeedLaser n/a Riegl Jenoptic UK 15-Oct-99
LTI 20.20 Ultralyte 100 n/a Laser Technology Inc Tele-traffic UK 15-Jul-99
LTI 20.20 Speedscope n/a Laser Technology Inc Tele-traffic UK 01-Apr-96
Unipar Urban Speed Ace n/a Unipar Services n/a 28-May-99
LDI Laser Data Interface Use with Autovision 3 (AV3) Traffic Safety Systems n/a 24-May-99
LDI Laser Data Interface Use with Kustom Prolaser II Traffic Safety Systems n/a 24-May-99
Cleartone Stealth Speedlaser n/a Cleartone Telecoms n/a 05-May-99
Speedmaster DS3 Use with Autovision 3 (AV3) Cleartone Telecoms n/a 24-May-99
Truvelo COMBI-S Use with M4 Squared piezo sensors, MPC Speedmeter and Robot DCE camera Truvelo UK Truvelo UK 15-Apr-99
Truvelo M4 Squared n/a Truvelo UK Truvelo UK 09-Aug-96
Lasercam Digital Camera System Use with LTI20.20 Locktronic Systems n/a 26-Feb-98
LASTEC Local Video System Use with LTI20.20 Laser Technology Tele-traffic UK 10-Feb-98
Micro Mercury Speed measuring system 90500 n/a Traffic Technology Ltd Traffic Technology Ltd 09-Aug-96
Micro Mercury Vision system 92600 n/a Traffic Technology Ltd Traffic Technology Ltd 09-Aug-96
Autovision 2 Use only with Speedmaster DS2 TSS TSS 09-Aug-96
Traffiphot S Speed Detection Device n/a Peek Traffic Peek Traffic 11-Mar-96
TSS Speedmaster DS2 n/a TSS TSS 09-Aug-96
TSS UK 15 n/a TSS TSS 01-Jan-87
Speed man Enforcement System n/a Golden River traffic Ltd Golden River traffic Ltd 09-Aug-96
Gatso Type 24 + AUS n/a Gatso BV SERCO UK 01-Jul-96
Gatso Mini Radar MK3 n/a Gatso BV SERCO UK 31-Jul-86
Gatso Mini Radar MK4 n/a Gatso BV SERCO UK 31-Jul-86
Muniquip T3 n/a Tribar Industries Unipar Services 31-Jul-86
MPH K15 n/a MPH Industries TSS 31-Jul-86
Kustom Pro Laser 11 n/a Kustom Signals Inc ISS 18-Sep-96
Kustom HR8 n/a Kustom TSS 31-Jul-86
Kustom HR4 n/a Kustom TSS 31-Jul-86
Kustom Roadrunner n/a Kustom TSS 01-Jan-87
Kustom Falcon n/a Kustom TSS 01-Jun-87
MuniQuip K-GP n/a Tribar Industries Unipar Services 01-Apr-95
SERCO Speed Enforcement System Type 1 n/a Gatso BV SERCO UK 24-May-95




GATSO units are named after the 1953 Monte Carlo Ralley winner and Indonesian immigrant to Holland, Maurice Gatsonïdes, who invented them. They are currently manufactured by Gatsometer BV., also in the Netherlands. The speed of a vehicle passing the unit is measured using a wide band Ka radar emitted from the front of the camera (the rectangular plate) in a 5o beam across the road, at an angle of 20o to the road. Ka-band radar (also known as photoradar) emits in a frequency range of 33.4000-36.000GHz. It measures your speed and if you're travelling above a pre-determined limit, trips the camera which in turn takes two photos of the back of your car - hence two flashes. It takes two so that the speed information superimposed on the resulting photographs can be manually double checked by calculating the distance the car has moved between pictures. As the pictures are taken half a second apart, and there are markings on the road at 2 metre intervals then the speed can be calculated.
This method is also used to confirm which vehicle is the target. If you contest the allegation on the grounds that "someone faster was overtaking me", a quick check of the photos reveals relatively which car has travelled further between them.

We have a new page to give advice on how you may avoid your speeding penalty click here.

These things cannot just be installed anywhere, there is meant to be some method to the madness, the rules in summary are listed here in Site Location Criteria

Where are the Speed Traps located - see our Speed Traps Where are they page

The actual radar unit takes between three and four hundred readings of a single vehicle as it passes through the beam. Within these readings, the variation in measured speed must not be more than 2mph. If it is, the radar unit aborts the test. The unit can also differentiate between large vehicles and cars by the amount of radar return, so a lower activation threshold can be set for large goods vehicles and coaches. This explains why sometimes you see a truck that is doing 70mph on a dual carriageway trip a camera when a car at the same speed does not - it has registered that the truck was going too fast (trucks are limited in top speed).
Most GATSOs are tuned slightly above the ACPO guidelines This is a very rough estimate, but it means that theoretically a GATSO in a 30mph zone will only register vehicles travelling at 35mph or more. Of course this is all tuneable by the officer who sets the camera, but those are the guidelines. This is to take account of the number of cases that would otherwise come back with people complaining that "my speedo said 30mph" and suchlike.

If you want to find out the detail of how these devices work then take a look at our How the Police Gadgets Work pages.

The Red Light GATSO
Known as the RLC (Red Light Camera), this is hooked up to the traffic light sequence and runs off an inductive loop in the road just after the stopline at the lights. When the lights turn red, the loop is powered up, and anything passing over it is photographed. These need only one photo to prosecute, but take two so there is a manual confirmation for the officer examining the film later. Recent changes mean that some of these red light cameras (which are in a smaller box) are having radars fitted so that they become speed cameras when the lights are green or amber, and red-light cameras when the lights go red. In Holland in particular, the inductive loop system has been refined to the point where the radar is not necessary and I know of at least three cameras now which look like red-light cameras but which also take speed-triggered photos when the lights are green.

The Stationary GATSO
Also known as the FIP (Fixed Installation Post / Position), this is the big grey box that we all know and hate. Interestingly, in the UK, the particular shade of grey which is used to paint these boxes is the shade which, under study, proved to be the colour least obtrusive to peripheral viewing. That's technobabble to tell you that they've deliberately painted them a colour which is very indistinct. In the Netherlands, some cameras are painted bright colours precisely to make them noticeable, thus making them proper deterrants. Take a peep if you want to see what I mean!
FIPs have two holes in the front. The top one is the camera, and the one in the bottom corner is the flash. The radar is inside. These work as described above and are generally infallible. They carry an 800-frame roll of film which is regularly changed, cost around £30,000 each and work at all speeds up to 155mph. Even if the site is a dummy, it still costs £3,000. Gatsometer BV. repair these units almost by return post so don't expect to find many faulty ones!
As you approach these units from the rear, look out for two holes in the back of the box at the top. There's a metal plate between the outer and inner skin that is used to protect the locks from the elements and from vandalism. If you find a site where the holes are visible, it probably means that the last person to service it forgot to lock it up properly. It's a tell-tale sign that the box has recently been fiddled with in some way - either to put a camera in, or change the film, for example. Be more careful than usual if you can see these lock holes uncovered.


According to Chief Inspector Phil Groves (ACPO), the ratio of live units to dummies in the UK in 1999 was 1 in 8. In other words, when you tear past one of those grey boxes, there's a 1 in 8 chance that it's loaded. This is because the flash and the radar unit are cheap, but the camera units themselves are prohibitively expensive. So dummy boxes can have the radar and flash in but no camera, which can give the effect of having been caught, but without any photo actually being taken.

The ratio of live working ones to dead ones seems to vary by county and council and almost monthly by budget, so do check out our News section to see the latest reports.

If you're interested in the ACPO site-location criteria for GATSO type devices, read the technical information on site criteria here.

One thing you need to be aware of that is being talked about for next-generation GATSO products: trying to make them work off inductive loops under the road like the RLCs. The reason for this is simply to try to prevent geradar detectors (such as the Bel990i) from picking them up. The cost would actually be more to do this because it would involve digging up the road instead of just plonking a pole down on the pavement. In the Netherlands, the birthplace of the GATSO, fibre-optic signs have been linked to some inductive-loop FIP sites now which inform drivers that they are going too fast.

The Dummy GATSO
Dummy GATSO's are a great deterrant. They look just like the real thing, they flash just like the real thing. They just don't take any photos. The camera is typically the most expensive part of a gatso installation, followed by the cost of the radar unit. GATSO can supply a cheaper, self-regulating radar unit that will hook up to the flashgun and fire it when a vehicle passes the camera travelling above a set speed. The dummy radar units are much simpler, and measure speed less accurately then their full-cost counterparts. Dummy GATSO units can be set to flash either once (which gives the game away) or more likely, twice (thus mimicking perfectly a fully operational unit.)

The real radar unit, and it's associated control box which connects it to the camera. The much simpler, self-regulating dummy radar unit.

The Double-sided GATSO
This is a derivative of the fixed-installation post as described above. The difference here is that the camera box is mounted in the central reservation of a road instead of at the side. The box itself has holes for the radar and camera on both sides, and the road is marked on both sides too. There's no way for you to know if the camera is live, but you can tell which way it's facing because it must be angled down to take the photos. The side angled up is the dummy side. The camera and radar unit inside the box are fixed, but the head can be oriented to face either way. There's also talk of an adaptation of these types to actually have two radar and camera units inside so they can monitor both sides of the road at the same time. There's little chance that this will actually happen though, as the unit cost is so much, the police wouldn't risk the loss of two units on one site by vandalism. Coupled to the fact that there's not enough room in a normal box for doubling-up of units, we can safely dismiss this as rumour-mongering by the police.
These double-headed systems entered service with the Dorset constabulary in early 1999, with the first units being placed on the A338 Wessex Way bypass.



The MiniGATSO (Portable GATSO)

The latest incarnation of these are called the GATSO MicroRadar. These bastard devices are the size of a small aluminium briefcase, supported on a small tripod about a metre off the ground. They use the newer Ku band of radar, and there's only one radar detector I know of on the market at the moment that can detect Ku. (see radar detectors for more info.)
MiniGATSOs can be poked through holes in bushes, hidden next to unmarked cars etc and are horrendously accurate. It means that the police can set up a speed trap in a matter of moments by having a portable GATSO poking through a gap in the trees or crash barrier, and then sitting just out of sight with the readout waiting for the unsuspecting motorist (picture on right) Alternatively, they can set up a complete automated photo-taking miniGATSO (complete with camera and flash) in a similar way (picture on left). Usually, this lot will work in pairs though. The operating officer will readout the speed to the arresting officer, and about half a mile down the road, this officer (in a luminous yellow smock) will jump out and hope you don't run over him. If you contest the issue, the photos will be developed and you will be prosecuted.


Mobile GATSO.
The Mobile Installation Post (MIP) is basically a complete FIP camera as described above, but mounted on a trailer. It costs around £9000, and entered service in the UK after extensive testing along the length of the A350 East Koyle bypass in 1997. It is towed to position behind a Range Rover or similar vehicle, and can be deployed in around 15 minutes. It has the same box on top of the pole as a normal FIP, and hence works the same (radar, 800 frame roll of film etc). The ruler markings on the road are the only difference. Obviously, the police can't paint these markings each time so they are superimposed on the pictures in the same way that your own camera might overlay the date and time on your holiday snaps.



Livelink GATSO type approval example

In May 1996, a new type of GATSO went through type approval by the DoT prior to coming online in the UK. It's now used in several locations, including on the M25. This is the live-link GATSO. No film, no guesswork, no messing about. The camera is not a stills camera but a live video or CCTV overlayed with the radar information, linked directly to a police monitoring station. Fast, efficient, and dangerous if you're in the habit of speeding past the boxes. The worst news is that these boxes will almost certainly work on the inductive loop method so there will be no early warning for those of you who own a radar detector. This livelink image is courtesy of a very lucky man, Gary van Hoek who wasn't fined, just warned. The numberplate has been blanked for obvious reasons. This particular photo was taken in a 50mph roadwork speed limit. Move your pointer over the image for an explanation of what each section is in the status bar of your browser. Click here to go to Gary's place.


Livelink GATSO Developments (from February 1999)
Experiments have been taking place (and indeed still are) with various different and brands of digital cameras, as indicated above. The application of non-intrusive (ie infra-red) electronic flashguns has also been under review in different lighting situations. It is now possible to monitor a 4-lane road with a single, high-resolution CCD camera. A 2-lane road can be similarly monitored with a single medium-resolution CCD camera. The resolution of both these cameras has been deemed to be more than sufficient for the application they are being used in. Just before the end of 1997, Gatsometer BV. set up a test site close to their factory in the Netherlands. Radar and camera units were live-controlled via an ISDN link from the factory testing facility. All recorded data (time, speed, images etc) were relayed directly to there. The system became available to police forces during late 1998, whereby it became possible to replace existing installations with this new technology. Police forces are now able to remotely determine when a camera is 'live' and when it's a dummy. They can also determine which direction it should face. No longer is the time-consuming task of on-site switching and film-replacement be necessary. This implies a greater "live time" for each installation. Bugger!
With future improvements, automatic license-plate identification will be possible. Current systems being tested for this application are producing a less than 0.5% error rate in correctly identifying numberplates. A similar system was tried and tested with great success in the roadworks on the M1 in England in 1996. The cameras were set to identify people travelling faster than 54mph in a 50mph imposed speed limit. Further down the road, the system was hooked up to a large electronic display which then flashed up the driver's speed and license plate for all to see. This had a twofold purpose. Firstly, it was used to make that driver accountable to all those around them, to attempt to embarass them to slow down. And secondly, it let the driver know that they'd been correctly identified, and would soon be seeing a fine and three (more) points on their driving license. So far, no commercially or privately available "stealth plate" has been able to fool this type of system, as it no longer uses a visible flash. In most cases, there will be no flash at all.

GATSO RampMeter.
In August 1998, a new Gatsometer technology started appearing - the GATSO Ramp Meter. It's a digital-based fixed installation post, similar to the red light camera. It is connected to a red traffic light at the bottom of an on-ramp to a motorway, and is designed to regulate the amount of traffic entering the motorway. In America, they make do with red lights alone, but here in Europe, red light law has to be enforced. If the red light is on, you stay on the on-ramp. When it goes out, you enter the motorway. If you pass it when it's on, the camera is active and will take your photograph. It takes a single frame using live-link technology and a digital camera to send the image directly back to enforcement-HQ. The photo and a modest fine will be in the post before you even get off the motorway.

Interpreting your GATSO photo.
Ff-flump. (kerswing). You're lying in bed and you hear the mail flop through your letterbox. You leap energetically out of bed, run downstairs and thumb through it. There, buried between the letter telling you that you've won £1,000,000 (if you buy a luxury yacht first), and your partner's girlie/bloke magazine is a manilla envelope. It might as well have "you're nicked" printed on the outside in 6 inch high letters. Yes, you're the proud owner of a photograph of the back of your car. The photos themselves are not usually much to look at, but the little panel in one of the corners of the image is well worth looking at, as it contains a wealth of information about your offence which you can double-check against both your own memory, and the offence as detailed in your NIP.

Firstly, this is the panel that will be printed on your photo should you have been caught skipping a red light:

Secondly, this is the panel that will be printed on your photo should you have been caught tearing past a speed camera above it's trip speed:


A loophole in the UK Law about GATSOs.
(source: Max Power magazine, August 1996) Tens of thousands of speeding UK motorists may have their convictions quashed after a loophole in the speed camera laws was recently uncovered. Police have been using computers to enhance the photographs in order to make the numberplates more visible, and easily identifiable. However, as only direct pictures from a speed camera are admissable as evidence, anyone convicted with enhanced pictures is entitled to a pardon. Convicted motorists should write to the courts demanding that their cases be reviewed.
Here's a first-hand account from Stefan Schulz, the second motorist in the UK to use this system to destabilise a claim:
About five months ago the joint Camera Detected Offences Unit of the Metropolitan and Surrey Polices (sp?) sent me a notice of intended prosecution about an alleged speeding offence on the variable speed limit section of the M25 near Heathrow. They said they had photographic evidence supporting their allegation.
I asked for the matter to be dealt with in court. It was, at Uxbridge Magistrates' Court, on 21 August 1996.
The CPS withdrew its evidence and I then had no case to answer. Costs were awarded from central funds.
So what happened ? Well, the police's / prosecution's case had more holes than you could shake a Swiss cheese at. For example: (the list is from memory, and therefore not exhaustive)

  1. Section 20 of the Road Traffic Offenders Act 1988 as amended by section 23 of the Road Traffic Act 1991 specifies that only evidence produced by the speed camera is admissible. As a matter of standard procedure, the CDO unit produces video prints and in my case even manipulated one, enlarging the rear view of the car only, but not showing any speed information. They were unable or unwilling to provide the negatives produced by the camera. Going from film to video prints to manipulated video prints clearly breaks the continuity of evidence.
  2. The speed recording units at the relevant section of the M25 are Serco Speed Enforcement Systems Type 1. It is a condition of their type approval by the Secretary of State for Transport that they be used singly, presumably to eliminate interference between the units. On the gantries above that M25 section they are used in arrays of three or four per gantry.
  3. It is a further condition of the type approval that the units be used with certain accessories. No mention of the existence, let alone use of such accessories was made in the written statements of the two police officers being submitted in evidence (and later withdrawn).
  4. Police witnesses did not turn up in court, despite my asking for them.
  5. The police did not provide positive proof that the recording equipment was linked to the variable speed limit signs so as to ensure that the speed limit triggering the recording equipment and the speed limit displayed on the gantries were the same.
  6. The police did not provide positive proof that the equipment was working at all, merely made a statement that 22 1/2 hours after the event an officer went to the equipment to remove a film and that he had "no grounds for believing that the information recorded was inaccurate".
  7. The police did not provide any proof of what, if any, precautions had been taken to prevent aircraft or airport radar from interfering with the speed measuring equipement.
  8. The police did not provide any proof of calibration of the equipment.

The angle regarding continuity of evidence or rather the lack of it was mentioned in an article by Barbara McMahon in the Evening Standard on 3 May 96.

If you want to find out the detail of how these devices work then take a look at our How the Police Gadgets Work pages.

If you want to find out where your local speed traps are then see here.

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