Peter
You probably know already that it is not a good idea to admit you have a radar detector in your car whether it is legal or not. The reason the officer asked this of you was because he could not get a constant speed reading over some time to support his position. You confounded that by putting on the brakes after your detector went off. As a counter point, the prosecution will argue, "That this is be best speed reading they got because you were using a radar detector. So, why did you change your speed if you were not speeding and why did you use a radar detector if you abide by the speed limit?" In my opinion, you will need to address these arguments.
Deeb,
I have been following the thread and I figure its time to wade in. George has excellent comments and should be fully considered. The book I referred to, covers much of the discussion - including the points about calibration, distance, time to get an accurate speed reading. Haven't seen all the http links but they look good.
With regard to your defence: After I received my very first speeding ticket in Toronto, I consulted with a lawyer. They said I should present a defence similar to what you have outlined. Which I did successfully. At the time, the high tech gear your car has, was not available so I had to use some of the arguments George mentioned. A word of caution, what I was told is that "Road and Track" cannot be used as an authoratative source for data in a court on its own. Backing it up by your in car shot is perfect.
There is one thing that I would repectfully add to your defence. I would also say something like: "The radar reading was taken at a time when I was accelerating. Acceleration, being a non-steady state where speed changes with time and distance, introduces a number of variables that can make a radar or laser speed reading not entirely accurate. In light of the evidence presented, it is not surprising to me that there is some question and doubt over the accuracy of the prosections' data."
So in my opinion your defence is super. It does what my lawyer suggested, uses physics, and physical data to creat doubt in the mind of the judge. So its up to the judge of the day on how it will go. Personally, your defence brings a smile to my engineering face. Well done.
Just a comment, George Dzioba, a neighbour and friend, who just retired from the crown prosecutors office gives me advice from time to time. I recall a discussion of the Highway Traffic Act and wondered why it was that the defendant seems to be put in a position of proving innocence (being assumed guilty) rather than being assumed innocent. His answer: "The Highway Traffic Act is written that way!".
HTH (Hope This Helps)
Good luck
Bohdan