A tip incase anyone gets caught 'speeding'

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Throbbe wrote: »

Generally the most significant error results from the measuring device being off-line from the direction of travel. However, this always reduces the 'observed' speed.

In a past life I used to measure vehicle speeds with a gun, and while it is possible to get errors, either deliberately, or through poor use, a trained operator can avoid them.

The ACPO guidelines are more about speedo error and giving people a little bit of leeway.

Thank you for that. Very useful.
Of course it is never possible to avoid errors completely, only reduce them.
I'm aware of the angular dependence when measuring the Doppler shift and this will reduce the measured speed. However, I wondered if it was corrected for - giving the potential for overcorrection.
Presumably you can also get errors from reflections from other things as well and errors related to which part of the car the gun is pointed at, or if the gun is held still (if not on a stand)