Speed camera operation in victoria
How do digital fixed speed cameras work?


How do the cameras detect speed?

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. Some fixed digital speed cameras also operate in conjunction with a measurement device known as a TIRTL which cross-checks vehicles' speed using a pair of laser beams that are aimed across the road a few centimetres above the surface of the carriageway.

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 usually 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 detected vehicle
  • Speed of the detected vehicle
  • Speed limit applying to the road where the camera is situated
  • The lane that the detected vehicle was travelling in
  • 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 Domain Tunnel for example, cameras have been installed and configured to monitor all lanes simultaneously. 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.

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.

The original image forms the basis of the evidence produced in court.


Eastlink fixed speed cameras

Digital fixed speed cameras are mounted under the bridges at Wellington Road and Dandenong Bypass, as well as in the Eastlink tunnels. These speed detectors are the Gatsometer Digital Radar Camera System—Parabolic (DRCS-P) which operate on radar, not piezo strips. 

These devices can measure and photograph vehicles in each lane on the northbound and southbound carriageways.

There has been a great deal of publicity about these cameras in the press. No court has ever found that the cameras are defective. Courts often dismiss speeding charges without ever make a finding that the speed measuring device is faulty. It is very unlikely any court will ever make a finding that the Eastlink cameras are defective. The best that a defendant could hope for is to cast doubt on the measurement such that the court can not be satisfied beyond reasonable doubt that the speed measurement is correct. 

The threshold of the Eastlink cameras is 108kmh, which means no photo is taken unless the speed measured is 108kmh or more. If you collected all the infringement notices issued by the police in respect of Eastlink and put them in piles corresponding to the speed detected, you would have a pile for 108, another for 109 and so on up to 200kmh or more. Without a doubt the biggest pile will be the the 108kmh pile. I would expect the 112kmh pile to be less than half the size of the 108kmh pile.  Some people claim that the large number of 108kmh infringements shows that the cameras are faulty. On the contrary, it indicates that the system is working exactly as you would expect.


Related Pages:
Speeding fines
Speed cameras
Demerit Points
Mandatory Sentencing




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