Technical requirements
Different camera systems are used in different locations.
Depending on the type of camera system operating at a location, the system may be required to:
- capture images to enable the identification of vehicles involved in an offence
- detect the direction in which a vehicle is moving
- differentiate between vehicles on a multi-lane road
- reference other traffic data (timing of traffic light changes, variable speed limits) to detect offences
- calculate the speed of vehicles using the time and distance data captured
- verify speeding incidents through an independent secondary technology (see information on Secondary Speed Verification)
- capture the time elapsed after the light has turned red (for red-light offences only).
Meeting these requirements means using a number of different components.
Components
The major components in use in the Victorian fixed road safety camera systems are:
- Road safety cameras
Road safety cameras are devices that are configured to capture images of traffic offences. The choice of devices is limited to those prescribed in the Road Safety (General) Regulations 2009.
A central control unit controls the camera and electronically stores encrypted images and incident information. - Speed measurement devices (SMDs)
- In-road sensors
The most commonly deployed SMDs use electronic in-road sensors. In-road sensors enable the detection of a vehicle’s speed. There are a number of types of in-road sensors, including piezos and inductive loops. An in-road sensor is used to detect the presence of a vehicle. Two in-road sensors are placed a fixed distance apart, so that a vehicle’s speed can be calculated using the time it takes to travel from one sensor to the other.
In-road sensors are also used to detect red-light offences by detecting the movement of a vehicle as it enters an intersection. If a vehicle enters the intersection after the traffic light signal has turned red, the sensors trigger the camera to take a photo.
In-road sensors are installed in individual lanes on roadways. This allows the system to differentiate between vehicles in different lanes. - Radar technology
Speed measurement devices (SMDs) using radar technology are one of the mechanisms used to detect the speed of vehicles. The devices prescribed for use in Victoria are listed in the Road Safety (General) Regulations 2009.
Radar technology is one type of SMD which measures a vehicle’s speed. This is done via the radar device sending out a signal transmitted by the radar device which ‘bounces off’ the vehicle and is then received back by the radar device. The frequency of the signal received back is different from the frequency transmitted and can be used to calculate the speed of a vehicle with high accuracy.
Another form of SMD is the optic fibre-loop-optic fibre system. - Optical character recognition
Optical character recognition software is a computer-based system that can read letters and numbers. This is used in a point-to-point camera system to read car number plates from photographs taken by cameras.
- In-road sensors
Camera data security
Victoria has strict security measures in place to ensure that all data captured by road safety cameras is kept secure at all times. This data can be used in court as evidence of an infringement.
The security of data within the Victorian road safety camera network is maintained through a range of mechanisms.
These security measures place strict controls on the use of any personal information collected through the road safety camera network. This ensures that the privacy of individuals is protected, in compliance with the Department of Justice’s obligations under the Information Privacy Act 2000.
