The Road Traffic Offenders (Prescribed Devices) Order 1993
This Order prescribes two types of speed detection devices for the purposes of section 20 of the Road Trafffic Offenders Act 1988, as substituted by section 23 of the Road Traffic Act 1991. The first is a device activated by a vehicle passing over sensors or cables on the road; the second is a device activated by a vehicle passing through light beams.