JOB-BLACK-RAT
MB Enthusiast
Police PILOT, the on-board speed detection device has a 7 day calibration that automatically 'drops out' after the 7 days.Did you notice "Calib. required" on the video ... presumably speed figures from that would not have been admissible as evidence (somewhat academic in this case!).
It must be recalibrated on a set and certificated distance when, 'calibration required' or when tyres are changed, it operates on a pulse system of tyre rotation and a new tyres would increases the tyres circumference and thus need to be changed. This recalibration must be noted in the vehicles log book.
Most pursuit and 'main set' type vehicles have a calibrated speedo, however this is done and certificated only once in the lifetime of the vehicle and should be used to confirm an Officers suspicion of excess speed.