There are three different types of speed cameras that motorists are likely to come across in their travels around South Africa.
Speed cameras are used as a deterrent to prevent motorists from exceeding the legal speed limit by issuing traffic fines that are used as a source of revenue by provincial governments and local municipalities.
This includes fixed cameras, portable radar scanners, and average-speed-over-distance monitors, and each one has its own method of operation that road users should be aware of.
Fixed cameras
One of the most ubiquitous types of speed traps are fixed cameras, which are installed at key locations in urban areas and along national roads.
These cameras typically use either piezoelectric strips or radar technology to detect infringements, according to MyBroadband.
With the first method, piezoelectric strips are laid out across the road surface, which are able to read mechanical or thermal inputs from cars passing over them.
These readings are then converted to electrical signals to determine whether or not the vehicle is speeding, and this information is then transmitted to a nearby camera.
If the person is recorded exceeding the speed limit, the camera will be triggered to take a photo of the car and its plates.
Alternatively, radar-based cameras will transmit radio waves at passing vehicles that are bounced back at the speed trap.
The returning signals allow the system to map a change in frequency as the car travels over a set distance, which determines whether or not a person is speeding.
Fixed camera traps can be deployed anywhere in the country that abides by the Technical Committee for Standards and Procedures guidelines, which govern parameters such as the distance at which cars can be recorded and whether there are any metal surfaces such as road signs that could interfere with radar-based systems.
Motorists also do not have to be warned about upcoming fixed cameras through the use of signs.
For a fixed camera to be able to issue a fine, it must provide the following information:
- Date of offence
- Time of offence
- Location code
- Speed measured
- No obstructions apparent
- At least two photographs indicating the vehicle’s position with a clear image of the number plate
Piezoelectric strip systems must also record a view of the whole width of the traffic line.
Motorists who are issued a fine without a photograph of the alleged incident can request one free of charge.
Portable scanners
Portable scanners are used by traffic enforcement and can be set up at strategic locations along popular routes.
The most common type of model used in South Africa is the X1-A scanner provided by Syntell, which operates as the camera service in Johannesburg and Pretoria.
These devices also use radar technology but are able to scan five lanes of traffic and up to 32 cars simultaneously with a capture time of just 0.5 seconds.
There are strict guidelines regarding how these scanners are used, and traffic officials are required to pass a course on speed measurement before they can be deployed.
According to the National Road Traffic Act, motorists can request copies of an official’s certificate for speed assessment to verify that the person is qualified.
If a certificate is not produced, the fine may be considered unenforceable.
The scanners themselves must also be calibrated every 12 months by an accredited facility that will issue a certificate to show that the device is usable.
The guidelines for speed traps state that mobile radars can only be set up over 300 metres away from a sign indicating a speed limit change, but no more than 500 metres away.
The scanner must also have an uninterrupted view of the car being monitored, which means another vehicle overtaking at a key moment could render the fine invalid.
Average-speed-over-distance
Average-speed-over-distance (ASOD) systems employ two cameras installed at key points along busy national roads, typically at the start and end of a frequented route.
The cameras are usually suspended above the road and scan a car’s number plate when it enters and exits the zone covered by the two monitors.
The system then calculates the vehicle’s speed based on the time it took to traverse the distance between the two points.
ASOD enforcement is more difficult to avoid than other systems, as motorists speeding through an area will have to slow down to lower their average speed by the time they reach the end camera.
While these systems are currently used to regulate portions of the N1, N2, and N3 in the Western Cape, Gauteng, and KwaZulu-Natal, the South African National Roads Agency (Sanral) is currently investigating the possibility of converting its failed e-toll gantries into ASOD law enforcement systems.
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