The Road Traffic Offenders (Prescribed Devices) Order 1999
This Order prescribes a speed detection device for the purposes of section 20 of the Road Traffic Offenders Act 1988, as substituted by section 23 of the Road Traffic Act 1991 (speeding offences etc.: admissibility of certain evidence). The device prescribed captures and records images of motor vehicles at two positions on the road and calculates the average speed of the vehicles between those positions.