Cameras can't catch the careless or dangerous driver, the drugged or drunk driver, the aggressive driver of the poorly maintained vehicle, but we are not here to discuss politics and how speed cameras are more revenue generating than you and I are led to believe. In the techie world of Lordpercy.com we want to know how things work and speed camera technology is an interesting area to explore, for this article our guest writer and long time friend of LP, "Huddro" has lent his technical expertise in radar and laser technology to "speed cameras explained"

Firstly we need to look at the type of technology deployed to measure the speed of a vehicle and then we can focus on the types of trap that employ this technology and how you can beat it.

The types of Trap - Radar

The name Radar is derived from the term radio detecting and ranging. It is a method of scanning by means of high frequency radio waves. The radio waves are transmitted out in a cone shape and reflect back from objects in their path. The reflected beam gives information on the speed and direction of the target vehicle.

Civilian radar frequencies were established at the end of the Second World War in the USA and the frequencies adopted by nearly all the other countries in the world.

The government originally used a frequency range called X band (10.525 Ghz +/- 50 Mhz and 24.150 Ghz+/- 100 Mhz), introduced in the 60’s but this is now commonly used in such things as automatic shop doors and thus can cause your detector to beep constantly.

The next switch was to the lower frequency K band (24.150 GHz+/-100Mhz Frequency Range 24.050-24.250 GHz), in the 70’s as this was more difficult to detect.

Ka band, (33.4GHz-36GHz. +/- 100Mhz), was introduced in Europe in the 80’s and is in widespread use throughout Europe it was recently introduced to the UK and along with K band  is the common source of frequency for Gatso cameras. The latest frequency is Ku, (10.70 - 12.75 GHz. +/ - 100Mhz) utilised in mini-Gatso cameras and very difficult to detect due to the low power employed by the actual cameras.

There are two types of radar unit: a permanent broadcast where a constant signal is transmitted and the reflected waves analysed (no longer very common as too easy to detect) and instant ON (Pulse radar). Pulse radar transmits only after the operator has selected a target, and only long enough to get a speed-reading, for example a Gatso speed camera. This makes pulse difficult to detect.

The one down side to radar is that the beams bounce off of static objects in a number of directions in an effect called radar reflection. It is therefore possible to detect these waves even before you have turned a corner! Radar traps can be as simple as hand held guns although these are being ditched for laser units, radar is most commonly used in Gatso cameras both fixed and now mobile vans with mini Gatso traps which can often be as small as a blue suitcase on a tripod.

The types of Trap - Laser


Laser stands for Light Amplification by Stimulated Emission of Radiation. It transmits electromagnetic radiation a little like your own microwave. The major difference being that light has a much higher frequency than a microwave.

The light beam from the laser is very thin at a range of 1000m it is only 3 metres wide compared to the similar radar beam that is minute! The biggest detection problem is that it takes only 0.3 to 0.7 seconds to acquire and register a target at an operational range of 800 metres.

Laser is used in Lidar type detectors (Lidar meaning Light Detection and Ranging). Now as you can see trying to detect a pulse of laser is pretty difficult. Laser use is mushrooming amongst UK police forces it is far more accurate and operates over a longer distance, typical traps are hand held or tripod mounted operated on foot or from a patrol car window and sometimes from inside vans on motorway bridges.


The types of Trap - Truvelo

Truvelo is a simple system that uses embedded magnetic stripes or piezo electric devices within the roads surface to calculate the speed of a vehicle as it passes over them, these cameras are typically a little different looking and are nearly always forward facing with the two tell tale strips about 100 yards away from the camera unit. Detection of this type of trap is only possible with GPS systems.

The types of Trap - Specs / SVDD

The next generation of speed camera technology uses video and good old fashioned timing to catch those exceeding the limit, the principle is simple, if you know the time it takes for a car to travel between 2 fixed points and take a picture of it at point 1 and point 2 you have a record of how long it took that car to travel the set distance. Get there in a time under the set time and you must have been speeding, in fact a simple calculation can give your average speed, the really bad news is this need not be limited to a pair of cameras but a whole stretch of road.

This method can work day or night and requires no film, using number plate scanning technology the ticket will be in the post before you even get home, detecting it is only possible with GPS systems.

Types of Protection

No protection method is 100% and a combination of technology and driver awareness is required.

Radar Detectors

These are largely imported American units, these claim to be "5 band" and that they can detect everything, well that's true including shop door openers and traffic lights, out of the "five bands" you only need worry about K and Ku used in Gatso style traps, X will tell you where Dorothy Perkins is and also where the traffic lights are. It is vital to buy a detector that you can switch off the redundant radar bands like the Bel 550 Euro.

Do they work? well yes they can give about a 200 meter warning of most radar traps and enough time to scrub speed off even when approaching a Gatso from behind which is no mean feat.

Laser Detectors

These do work but they have a very tough job, if the laser is targeted on your vehicle then it will sound but you'll have already been nicked! your only hope is that in targeting the car in front some of the laser is deflected and picked up by your detector, unlikely but it does happen. In reality laser detection is included in nearly all other kinds of detector its not worth paying for on its own but as a freebie then ok.

Laser Jammers / Diffusers

These are illegal as they distort the reflected laser signal before it gets back to the unit, you will be in big trouble if you are caught using one of these far worse than the speeding ticket, do they work? well all we can say is why would anyone risk using them if they didn't!

GPS Systems

if you had a map of where all the fixed traps were you wouldn't accidentally speed past one would you? well no! and that's the simple premise that GPS speed camera systems work on, the GPS technology located your vehicle within a 5 meter accuracy and overlays this onto a map of the UK speed cameras. As you approach a site you are warned and it really works! of course the map has to be up to date which is not an easy task but a number of systems like the Road Angel cope well, of course these won't know about mobile traps!

So what's the answer? well I could say don't speed and I would if cameras were only used in areas where pure speeding was causing accidents, but we've all seen them on straight open stretches of roads, behind trees or signs. Coupled with the fact that the caused by "speeding " box on the governments figures is made up of a number of other factors like weather which masks that speeding is the main cause in only 7% of accidents.

The best technological answer is to get some assistance so that you don't forget or miss a camera location or mobile trap, if its so important that the police will have an officer sat in a van there then you should slow down and a speed trap detector will help you do just that. The pick of the crop for us is the Origin B2 which detects all types of trap.

To check out the systems available visit our Speed Camera Detector Reviews page.

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