Legal i

Legal I – Speeding and technical requirements of the prosecution

Last month, we looked at technical defences to speeding charges and we will follow with a series that analyse specific speed detection device types, but first let us look this month at the technical requirements that the prosecution have to observe when using technological aids in evidence, regardless of the specific device.


If the prosecution wishes to rely on evidence of a ‘prescribed device’, they have to provide the motorist with a documentary record produced by the device, accompanied by a signed certificate as to the circumstances in which that record was produced. This requirement applies to traffic light signal offences, speeding offences (including motorway speeding), speed restrictions related to road works, temporary minimum speed limits and some bus lane offences, but the list can be extended, or reduced, in the future.


Such a record is allowed in evidence in court only if the device is of an approved type (a ‘prescribed device’) and a copy of the record must be served on the motorist not less than seven days before the trial. If the motorist wants to question the person who signed the document in court, he must give notice to the prosecution of this wish not less than three days before the hearing.

What is a ‘prescribed device’? It is a device listed in a government order. There are a great many prescribed devices, but they include bus lane detection devices, radar speed measuring devices, speed measuring devices using sensors or cables near the surface of the road and by light beams, and average speed recording devices. Accordingly, if a charge of speeding is to be defended, and the alleged speed has been recorded by a device, then it is important to check that the device used is on the approved list. If it is not on the list, then the evidence produced by the device cannot be used in court. A Police Pilot Provida in-car speed detection device is not a prescribed device, so the fact that many police cars have it installed does not mean that the evidence from it can be produced as evidence in court.


In the next issue, we will start looking at some commonly used devices, starting with radar speed meters.


Designed by solicitors, tested by barristers and available around the clock, Road Traffic Representation is an online legal system that allows people accused of a motoring offence to get free advice on how the law will be applied in their case, and referral to a telephone helpline and representation by a barrister in court if required. Practising solicitor Martin Langan spent two years designing the system and creating the data repository which allows the software to analyse road traffic offences with the same authority as a solicitor.

Twitter: martinlangan

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