Gatso
Gatso speed cameras use radar technology to measure how fast a vehicle is traveling. If a motorist is driving above the speed limit for that road then several photo are then taken of the vehicle. The Gatso uses a powerful flash to show the rear of the vehicle, its registration plate, and calibration lines on the road. Gatso speed cameras are always rear facing. The reason for this is that the speed cameras 'flash' will not blind oncoming motorists. However, this also means that the speed camera may not be visible until the last second.

Truvelo
The Truvelo camera uses piezo sensors to calculate a passing vehicles speed. A total of four piezo sensors are embedded into the roads surface. As a vehicle drives over of these the time difference between sensors measures and calculates the passing vehicles speed.
In addition there are a further three white painted lines on the road just before the camera. When the Truvelo camera is triggered a photo using an infra-red flash (so not to blind) is taken of the offending vehicle; the photo is taken when the offending is on the central white line and are the other two are +/- 10%. This acts as a secondary method to calculate the vehicles speed and is a legal requirement for unmanned speed enforcement devices in the UK.

Truvelo D-Cam
A new digital Truvelo speed camera is being installed, known as D-Cam which is short for Digital Camera. Unlike the original Truvelo speed camera, these new cameras can be installed forward or rear facing to approaching traffic.
They can also be used as red light camera and can monitor traffic on 3 lanes at any one time.

Specs
SPECS average speed camera systems utilise state of the art video system with Automatic Number Plate Reading (ANPR) digital technology. These cameras are each fitted with infra-red illuminators fitted on gantries above the road, so they can work day or night.
SPECS speed cameras are located in multiple (at least 2 at a minimum of 200 metres apart) locations along a single stretch of road for monitoring your average speed along that particular road. So unlike other speed cameras which capture your speed at a certain point in the road, SPECS average speed camera work and track you speed over a set distance, which may be several miles!

Speed spike

SpeedSpike is the latest speed camera to take the UK's road and is currently being trialled on the roads in Hampshire, before a national roll out?
SpeedSpike works similar to SPECS average speed camera measuring over a set distance rather than at a fixed point like the popular Gatso safety camera.
SpeedSpike uses ANPR (Automatic Number Plate Recognition) and each time a vehicle passes the camera the number plate is read and time-stamped together with the cameras information. It is claimed by the manufacturer that up to a 1000 cameras can be linked and this is achieved via GPRS (or ADSL) and provide automatic enforcement, 24 hour operation, 365 days!
The SpeedSpike cameras can be mounted on gantries or on roadside posts. The actual enforcement speed may be independently set as site-A to site-B and site-B to site-A, with each link having a separate enforcement speed if. Speeding offences are detected between any SpeedSpike camera on one site and any camera on another site.
Look out for them as you drive through Hursley in Hampshire where they are on trial. Though if you're nowhere near Hursely and they prove success they may be coming to a road you drive soon?! Trafficmaster

These are not police speed cameras. They belong to a PRIVATE firm that uses road side cameras to monitor traffic speed and congestion levels. Information is sent to drivers whose satellite navigation systems have Traffimaster built in. This helps the sat-nav to avoid traffic jams. Police could get a court order to force Trafficmaster to hand over data, but they would be unlikely to do so for traffic offences.

Speedcurb

The SpeedCurb fixed speed camera is often used to