South African law enforcement agencies have long employed various types of speed traps to catch speedsters in the country.
Each type of speed measuring technology puts certain requirements on the operator – and their setup – for it to be legally used.
Justice Project South Africa chairman Howard Dembosky said these requirements are covered by the Technical Committee for Standards and Procedures (TCSP) guidelines.
“A change made in December 2012 legalised the deployment of unmanned speed measuring devices of a non-permanent nature and since then, the use of radar-based unmanned traps has mushroomed,” said Dembovsky.
He said, in his opinion, this change was unlawful.
There are four types of speed traps used in South Africa – this is what you should know about them.
Fixed speed cameras
Speed cameras mounted at fixed positions can use a number of techniques to measure the speed of a passing vehicle. They could also be used to monitor cars driving through red traffic lights.
Should you exceed the speed limit while driving through the camera’s field of view, or drive through a red light it monitors, it will take a photo for evidence.
A common method of speed measurement used with fixed installations is piezoelectric strips laid across the road surface. Alternatively, electromagnetic induction may be used.
These cameras can be installed in any location which conforms to the TCSP guidelines, and law enforcement officials need not put up warnings that they are trapping in the area.
The photo taken must show the following information:
- Date of offence
- Time of offence
- Speed measured
The vehicle must be clearly identifiable as the offending vehicle.
RADAR speed guns rely on the Doppler effect to calculate the speed of a passing vehicle by directing a microwave signal at it.
As with fixed installations, law enforcement officials are not obliged to warn the public that speed trapping is taking place.
However, after the speed trap is set up its operator may not touch it while it is in operation.
Officers who operate these devices also need to be in possession of a valid operator’s certificate, as well as a valid calibration certificate for the instrument being used.
When used to measure the speed of normal cars (class B1 and B2 vehicles), the following restrictions apply:
- No metal road signs, or vertical flat surfaces larger than 1m in vertical height, are allowed within 15 degrees on either side of the aiming direction, within a distance of 100m of the antenna.
- No high-voltage overhead power cables in the radar’s field of detection for at least 100m.
LIDAR uses laser technology to calculate the speed of a vehicle by sending two short pulses at its target.
It measures how long it takes for the two pulses to be reflected back, then uses the delay between the two to calculate the speed of the vehicle it was aimed at.
As with RADAR guns, law enforcement officials are not obliged to warn motorists they are trapping, but operators must have a valid operator’s certificate and calibration certificate for the instrument.
For LIDAR, the following restrictions apply:
- No measurement may be locked beyond 500 meters.
- When viewed from the gun, there must be a clear, visible separation between the target vehicle and any other visible vehicle.
- If no photographic evidence is available, the measured distance between the gun and the vehicle must be recorded on the charge sheet.
Average speed over distance cameras
Average speed over distance (ASOD) systems are installed in a number of places around South Africa.
The systems are highly visible, and ASOD areas are also clearly marked.
ASOD uses automatic number plate recognition through specialised cameras to detect when a vehicle passes a certain point.
The timestamp on the photo at the start of a stretch of road being monitored is then subtracted from a timestamp on a photo taken at the end, and the average speed calculated.
Requirements for speed measuring equipment in the TCPS guidelines hold for ASOD systems. The following requirements specific to average speed prosecutions also apply:
- At least two images with description of location must be recorded, one at the start location and one at the end location.
- Date of offence and time of offence must appear on the images.
- Information on the image, and the information on the National Register of Vehicles, should correlate with regard to the make and type of vehicle, unless the photos were taken in adverse weather conditions or between sunset and sunrise.