Free Traffic Legal Advice

Contesting 47 in a 30 (Band B) - Forensic GPS contradicts Police Allegation
 
Hi everyone,
 
I am seeking advice on a potential "Not Guilty" plea for an alleged speed of 47mph in a 30mph zone. I currently have a clean license (0 points) and want to protect it.
 
I have a significant discrepancy between the police allegation and my phones verified GNSS (GPS) telemetry for the time of the stop.
 
The Case Context:
 
1. The Allegation: 47 mph (Band B).
2. The Setup: I was towing a heavy piece of plant machinery on a trailer.
3. The Road: A downhill gradient with a very short total journey distance (~800m/ 0.5 miles).
4. The Evidence: I was stopped at the roadside (front-facing laser)shown 47mph. I have been told over the phone that no photographic/video evidence exists.
 
The Telemetry Data (3m accuracy):
 
- My peak speed for the entire journey was recorded at 12.96 m/s (approx 29 mph).
- At the timestamp provided on the police documentation, my telemetry shows the vehicle had already been fully stationary (0.0 mph) for over 30 seconds.
 
The Proposed Defense:
I believe the 47 mph reading is a technical error (likely "Slip Error") caused by the combination of the downhill slope, the vehicle pitching under braking, and the complex reflective profile of the heavy equipment being towed. Furthermore, there appears to be a clear time-synchronization error in the police log.
 
Current Status:
The Justice Unit has declined to review this data at the Conditional offer, stating that evidence will only be provided at court.

The Conditional offer doesn't state the speed I was doing.

I've sent an email with screenshots showing the speed I was doing on the stretch of the road from exiting a roundabout , mid point , just before turning left to a side road where I was pulled and stopping time.

 
I am prepared to go to court to keep my license clean. Does this level of telemetry (3m accuracy) usually carry enough weight with a Prosecutor/Magistrate to highlight a technical error? Are there specific "procedural" questions I should be asking once I receive the SJPN?
 
Any advice would be greatly appreciated.
 
 
 

The timestamp difference is unlikely to be relevant unless it's wildly different.  (Without knowing the specific device it may not be GPS synchronised anyway - 'proving' you were stationary at the 'exact' time isn't going to cut it)

It appears to be a corroborated measurement by a laser device without video evidence.  (That, in itself, is not fatal)

A virtually instantaneous laser measurement versus telemetric system with low accuracy and averaged measurements.  You would likely need an expert witness from the system's makers - they may well decline and may state the system is not designed for such use anyway.

It seems a was a frontal ping, so not sure of the relevance of items being towed?

A 'slip error' requires a smooth movement of the device across a flat surface to fool the device into reporting a higher than actual value - a 'complex reflective profile' (if even scanned) would most likely trigger the reading to be abandoned.  The officer's statement will obviously be a factor.

That gets expensive very quickly.

As this chap discovered:



The court will have two lots of evidence:

One from a device that is approved by the Home Office and, as the prosecution will say, was operated in the correct manner.

Another from a device that is not approved and which you have operated.

The question for them will be to decide whether the measurement from the unapproved device casts sufficient doubt on the accuracy of that from the approved one (which is presumed to be working correctly unless the contrary can be shown). If, after considering that, the court cannot be sure that you committed the offence (which is exceeding the speed limit, not travelling at any particular speed) then you must be acquitted.

There quite a few factors to be taken in consideration but they didn't wanted to provide any type of evidence and been declining everything that I was asking.

The idea of the fixed penalty offer is that the driver accepts the allegation as it stands. This sees the matter dealt with at considerably reduced costs to both parties. Even if no expert evidence is required, a conviction following a trial in the Magistrates’ Court will see you walk away with little change from £1,500. So the police will not enter into any correspondence or debate about evidence and certainly not of a technical nature such as you describe.

What do you mean by a “forensic GPS”?