This Order prescribes a type of device for the purposes of section 20 of the Road Traffic Offenders Act 1988 (c.53) (speeding offences etc: admissibility of certain evidence). Section 20 provides for the admissibility of evidence in relation to certain road traffic offences where that evidence is produced in the form of a record from a prescribed device and where that record is accompanied by or contains a certificate as to the circumstances of its production which has been signed by a constable or by a person authorised by or on behalf of the chief officer of police for the police area in which the offence is alleged to have been committed. Section 20(4) provides that the device must be approved by the Secretary of State and any conditions to which the approval is subject must be satisfied if the record produced or measurement made by the device is to be admissible as evidence of a fact relevant to proceedings for an offence to which section 20 applies.
Link: The Road Traffic Offenders (Prescribed Devices) Order 2019
Source: Legislation .gov.uk