How do Fixed Digital Speed Cameras work?
How do the digital cameras work?
The fixed speed cameras detect the speed of vehicles by using piezo electronic detectors embedded into the road surface. These piezo detectors deflect slightly when a vehicle is driven over the detectors, which then triggers an electronic device that accurately measures the speed of the vehicle. If the speed of the vehicle exceeds the legal limit then a digital picture is taken of the offending vehicle.
What does the camera record?
If a vehicle is detected speeding, a digital image of the vehicle is recorded onto a disk from which all details regarding the speeding vehicle can be extracted. The image clearly shows the colour, type, make and number plate of the vehicle. Fixed digital speed cameras have the capacity to measure speed in both directions.
Digital images also include the following particulars:
- Date of the offence
- Time of the offence
- Location details of the camera which took the picture
- Direction of travel of the offending vehicle
- Speed of the offending vehicle
- Speed limit applying to the road where the camera is situated
- The lane that the vehicle was travelling within
- Other security and integrity parameters
How do the fixed speed cameras work in multi-lane situations?
Fixed speed cameras can monitor one to four lanes in the same direction. In the Eastern Distributor, northbound for example, cameras have been installed and configured to simultaneously monitor all four lanes. This is achieved by the installation of piezo detectors for each lane and of a wide angle lens camera, which monitors all lanes, and a telephoto lens camera, targeting each traffic lane. Therefore it is clear which vehicle has been detected. Vehicles cannot avoid camera detection by straddling lanes.
Can the cameras identify a speeding vehicle in a line of traffic?
A speeding vehicle can be detected and photographed even if it is within a line of vehicles. The angle at which the cameras are set enables pictures to be taken even if another vehicle is in close proximity.
How do I know that information recorded is secure?
The original recorded images are stored electronically on a WORM (Write Once Read Many) disk, which cannot be overwritten or altered. A security indicator is also produced when the file is written to the disk and should any attempt be made to tamper with the image at any stage, this is obvious to the relevant technician viewing the image.
Where the image is electronically transferred, all images and relevant information (such as time, date and location) is encrypted. Thus, the image cannot be viewed without the appropriate encryption key.
The original image forms the basis of the evidence produced in court. In line with legislative requirements, the photographs from fixed, digital speed cameras can be tendered as evidence in court, together with appropriate evidentiary certificates signed by an expert.
How do I know that the camera system is accurate and reliable?
The digital speed camera system (including the digital camera recording device and the associated speed-measuring device) chosen for NSW has undergone a comprehensive evaluation and testing procedure to ensure its accuracy and reliability. Experts, authorised by the RTA, inspect each camera system and verify its accuracy and proper operation prior to the commencement of the camera operation and thereafter at regular intervals. The camera recording device is inspected every 30 days and the speed-measuring device is inspected at least every 12 months in line with current legal requirements. An inspection is also conducted following any maintenance or repair of either of these devices.
