Verification and System Testing

In the UK, every speed camera must be calibrated and certified before the images from it are acceptable to the court, including the cameras used in police vehicles. Several speeding prosecutions have failed in the UK due to out of date calibration certificates.

The pictures taken by road-rule enforcement cameras must usually be viewed by a person before any infringement notice or ticket is issued to the driver, and judged to be satisfactory or not. This step is known as verification, and is a standard legal requirement in nearly all jurisdictions. Verifiers typically must check some or all of the following:

  • that there is no sign of interference with the vehicle detector by objects other than the alleged speeding vehicle,
  • that the licence plate is unambiguously readable according to a legal standard,
  • that the make and model of vehicle matches that recorded by the licensing authority for the number plate, and in some jurisdictions...
  • that the appearance of the driver in the images is adequate in some way - for example, that it matches the picture on the driving licence of the vehicle's registered owner.


In most jurisdictions, verification is carried out by the police force, although in many places it is carried out by private companies on a fixed-price basis under close police supervision. Generally, cameras must undergo approval testing and operational testing to ensure that they function adequately. In the United States, it is common for all installation, operation, and verification procedures to be carried out by private companies that receive payment based on the number of infringements they issue, and often under no testing regime whatsoever.

Depending on the number of things that need to be identified in the images and the quality of the camera equipment, somewhere between 35% and 80% of infringements result in a notice being issued to the owner of the vehicle. A legal requirement for driver identification reduces the prosecuting rate dramatically.



This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Red-light_camera".