Under the provisions of the Road Traffic Offenders Act 1988 certain traffic law enforcement devices require type approval by the Secretary of State before evidence from them is admissible in court. Type approval is granted only to devices that comply with the specification laid down by the HO Scientific Development Branch (HOSDB) and successfully complete both field and scientific testing. The type approval process provides a public reassurance that a device is accurate, consistent and reliable. Three variants of the LTI 20.20 system were type approved in the 1990s. We are satisfied that the device merits its type approval and have seen no reason to conduct further assessments.