Types of speedtraps

Types of Speedtraps used in the UK, As of January 2003

Radar or Laser
Non Radar or Laser
Non Mobile
Radar, Laser and Speedtrap Bands.
Speeding Offence Codes and Speeding Points System.

Radar Devices
Speed detection using radar was pioneered by Maurice Gatsonides, he was a rally driver who wanted to measure the speeds of rally vehicles, this turned into a business. Hence Gatso cameras.

Gatso Camera, Fixed Installation Post (FIP)
Usually has an 800 frame roll of film(some may now be using digital cameras). Operates on K Band.
When a vehicle exceeds a preset speed threshold, the device is activated taking two photographs half a second apart. The photographs show the date and time of the offence, together with the speed recorded. The unit takes between three and four hundred readings of a single vehicle as it passes through the beam. There must not be a greater speed variation on all of these readings of more than two miles per hour or the device will abort the test.
These can also use the TruVelo system or the inductive loop system.

Initially developed as a red light camera but has recently been made an addition to the arsenal of speed cameras, the Monitron works in a similair way to the Gatso cameras, above. There are sensors placed in the road in front of the camera and when a speeding car passes by the camera takes a picture. The main difference to the Gatso is that the Monitron uses a digital camera which then stores the images in a nearby device. Once the memory is full this is then automatically downloaded and wiped so the capture process can start again. The only way to detect this type of camera is via a GPS unit.

Mobile Gatso Cameras, Mobile Installation Post (MIP)
This is a complete FIP camera but mounted on a trailer. It costs around 9000 and is towed into position, typically in road works. It 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, the police don't paint these markings on the road each time, so they are superimposed on the pictures. However they do paint the road in some areas, like long term roadwork's.

SPECS, SVDD (Speed Violation Detection Deterrent)
Super efficient, 2 cameras with infra red that are linked to a computer that has number plate recognition, if the same number plate appears at the second camera within a given time period then it will calculate the average speed over the distance, if the speed is over a given threshold an NIP (Notice of Intended Prosecution) will be issued. All this can be automated by the computer technology it has, it can dial into DVLA for the driver details, and send an automated NIP with all the details and digital image, it won't run out of film like a Gatso can.
A company called Speedcheck will operate the system and so free up officers to chase real criminals. However this also means that because of the reduced police presence on the roads the nutters who keep to the speed limits but are just very bad drivers (such as the centre lane owners club) won't get stopped at all.
Motorcyclists are not affected by this system as it is forward facing so can't read a motorcyclists number plate. Square and dirty number plates can give the system problems.

uses three Piezo sensors installed in the road surface at known
distances apart. When a vehicle passes over the sensors, two speed
measurements are taken, the first between sensors 1 & 2, the other between 2 & 3. As with other systems if the difference between the two speeds is
greater than 2 mph the reading is regarded is void. The sites are normally
manned and the equipment is connected into a nearby Haldo pillar where the sensors are terminated.

Truvelo use a similar principle but use four Piezo sensors. The distances
are as follows:

1 - 3 = 1.53 m
2 - 4 = 1.53 m

There are a few different setups available to the users.

Fixed (Front)

Piezo sensors are installed in the road ahead of the post. When a vehicle
passed over the sensors two speed measurements are taken primarily between 1
& 3 and 2 & 4. However the camera unit is a bit more intelligent than the
dummy flash and actually double checks itself by taking measurements between
1 & 2 and 3 & 4. Again if the two speed measurements are more than 2 mph
different then the measurement is classed as void. There are three white
lines after the sensors which act as secondary check lines. Similar to the
Gatso lines in principle and are required by ACPO to prove that there is a second way of confirming the speed and you are not just relying on the radar or sensor measurements. The middle white line is 1.8 metres from the last sensor, the other two are 18 cm before, and 18 cm after. This is to allow for a 10% margin of error. Because this distance is exact the camera will take a photograph of the vehicle when the front axle (wheel) is on the middle white line. The camera knows your speed and therefore when to take the photograph.

Fixed (Rear)

Same principle but the sensors are placed after the post in the direction of travel. Speed measurement is the same and the first photgraph is taken with the wheel on the white line. A second photograph can be set to be taken either 1/2 sec later or when the vehicle has travelled xxft. Using Gatso style lines it is then possible, depending on the
setting, to prove that the vehicle was travelling at that speed. There are only two known locations where this system is used.

A15 Brant Road, Lincolnshire
A51, Tamworth, Staffs

Fixed Mobile

Four sensors again and the setup is much like DS2. Installed in the road
and with white lines the camera is attached to a tripod and run from a
battery. Manned, the officer can then sit in a car and keep an eye on the
equipment. Rear photography is also possible using the above method. There is also a remote control available ( a box on the end of a piece of wire plugged into the cable) allowing the user to alter the speed threshold for HGVs etc. NB: Becuase the Truvelo system cannot tell the difference between different vehicles HGVs travelling on roads where their speed is further restricted cannot be penalised. They would have to be travelling over the normal threshold for other vehicles.


Four Piezo tubes are placed across the carriageway at the same standard distances. A camera is connected and then it is active.

This is not yet used in the UK, it uses 2 infra red beams and 2 reflectors in the road, the beam is broken to activate it, giving speed, direction, the distance from the previous car, even the car length.

Cat's Eye Camera
Solar powered and already in use in America and South East Asia, feelings are that this is not yet proven technology for the UK and still has a long way to go, the government has commented that it is happy with it's current developments on speed cameras. More Information.

Portable Devices

Very accurate but the beam does spread out to 3 ft at 1000 ft distance.
When used over 400 yards they need to be tripod mounted for stability and are often used in a van, such as thes Cheshire 'Safety Camera Speed Enforcement Vehicles'.

Cheshire Safety Camera Speed Enforcement Vehicle. 2 Cheshire Safety Camera Speed Enforcement Vehicles. The video and speed offence recording equipment. The laser gun with digital speed readout and LCD panel.
Cheshire Safety Camera Speed Enforcement Vehicle. 2 Cheshire Safety Camera Speed Enforcement Vehicles. The video and speed offence recording equipment. The laser gun with digital speed readout and LCD panel.

Readings can be taken in a fraction of a second. It needs a flat reflective surface such as a number plate or even a headlight. The device must be calibrated once a year by the manufacturer and also at the start and end of each shift by the officer with a calibrated speedometer. The distance to the target must be a minimum of 10 times the height from the road.
Popular in Kent, Manchester, Cheshire and Wales forces, but fast becoming the most popular form of mobile trap across the country. The device can be switched for oncoming or receding vehicles. On an interesting note the Lti 20-20 has been banned in certain American states as the shake effect when using a heavy hand held device can affect it's accuracy.

Mini Gatso
This can be supported on a small tripod about a metre off the ground. Hidden next to unmarked cars, Motorway bridges and in the bushes. They are very accurate. K or Ku band. However police now prefer Laser devices.

Vascar (Visual Average Speed Computer And Recorder)
Set at a minimum distance of 1/8 of a mile. The trap could be white squares or round markings on the road but could be any fixed objects of a known distance apart. A police officer uses a time recording device to record the length of time it takes a vehicle to travel through the speedtrap, once this has been done it is a matter of time over distance to calculate the drivers speed. This could even be done from a helicopter or an officer on foot. As this is largely down to human judgement there is a tolerance for the officers reactions. The tolerance is the same at each end of the reading so the reading is thought to be accurate enough for a prosecution.. This can be used in conjunction with video for a safer prosecution.

This is an in car video system which can be used for recording poor driving behaviour and then be shown to drivers to demonstrate their errors, it can also be used in court to support the officers statement if needed.

Calibrated Speedometer.
An officer can simpy follow a speeding vehicle using a calibrated speedometer this must be done over at least 2/10 of a mile.

This is a hand held stop watch calculating and indicating speed. It can be used on foot.
An officer can make use of special markings in the road, police motorcyclists like to use them because of there portability being hand held.

Bus Lane Enforcement Cameras
Not quite a Gatso, but in some cities Bus Lane Systems are being used to monitor bus lanes, using Gatso style systems with inductive loops or Inboard Bus Video Systems. (The Video fitted on the bus can usually be seen fitted on the front in the middle area of the bus, a 9" square black window gives it away.) These cameras watch out for offending vehicles using the bus lane to drive down or park in. Offending vehicles get an NIP in the post.
In use around London they are proving very effective in convicting drivers that use bus lanes.

LTI 20-20
This is one of the standard laser guns used by the British police forces

Kustom Falcon


AutoPatrol PR100, Ka band 34.6 GHz

Speed camera, this sign can be used for almost any speedtrap device that they choose to put up including Gatso, mobile devices and so on..

High visibility speed cameras are to become the norm, starting with Norfolk region then, Cambridgeshire, Cleveland, Derbyshire, Essex, Lancashire, Lincolnshire, North Wales, Northamptonshire, Nottingham, South Wales, Staffordshire, Strathclyde, Thames Valley and Warwickshire. the cameras will be painted bright yellow and signs will have to be positioned according to the guidelines. They must be visible from a distance of 66 yards in a 40mph limit and 109 yards in areas above 40 mph.