Safe Speed Forums

Does anyone know if the calibration procedure for a Truvelo Combi C calls for a time check? I ask because a friend has been sent an S172 notice but the time of the alleged offence is about three hours after he actually drove down that road. He has a GPS system. He downloaded the GPS data and checked the journey time and speed in front of witnesses - so he can show that his car wasn't at the camera site at the alleged time. His GPS shows his car was stationary outside a coffee shop at the alleged time and that his average speed was within the limit at the time he actually drove down that road.

I've sent him off to PePiPoo, but in the meantime I suspect that an error in the camera clock may mean the camera was not operating within approved specifications, and so any evidence from that camera should be inadmissable. If that's so, then anyone caught between then and the next calibration should be able to get their case dismissed.

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Will

Perhaps he'll have to prove that his GPS was operating to the correct time?

The GPS time is transmitted from the satelites, which are kept accurate by atomic clocks. So, his GPS time data is guaranteed for accuracy. AFAICT, the questions are whether time checks are required for calibration and whether a three-hour error in alleged time of the offence is an "allowable slip".

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Will

My feeling is that the time error would win in an s172 case, but may be allowable slip in a speeding case. So this one (especially) would have to be played correctly.

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Paul Smith
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