How Do We Know Red Light and Speed Cameras Work

How do we know cameras work? Victoria’s network of road safety cameras deters drivers from speeding and disobeying traffic lights by increasing the chance they’ll be caught and fined for breaking the law. Most of us come across cameras almost every day, but may not know how they actually work. There are two types of cameras – mobile and fixed. Mobile speed cameras are installed in unmarked cars that transmit a radar beam across the road. When a vehicle passes through it, the beam changes frequency, measuring the vehicle’s speed. [Beep] If the driver is travelling over the speed limit, a photograph of the vehicle is taken. [Camera clicks] Intersection cameras detect speeding vehicles using two in-road sensors positioned a set distance apart. They determine the vehicle’s speed by measuring the time it takes to travel from one sensor to the other. If the vehicle is exceeding the speed limit, [camera clicks] then the camera is triggered and a photo is taken. Some fixed Freeway Cameras are installed above the flow of traffic. Like mobile speed cameras, these cameras transmit a radar beam which bounces off the moving vehicle and back into the camera. This provides a highly accurate measure of the vehicle’s speed. If the speed detected is higher than the speed limit then a photo is taken. [Camera clicks] All speeding offences recorded by fixed cameras are subject to what is called Secondary Speed Verification. This means that every incident is measured twice, independently, and these measurements are compared for consistency before a fine is issued. Even though cameras are highly accurate and tested regularly the system is fair to motorists by allowing a small, legislated, tolerance in speed of 2 kilometres an hour for fixed and 3 kilometres an hour for mobile cameras.