there is only one way to solve this once and for all. repeat the event under controled legal circumstances and no one will be able to argue. i am thinking something along the lines of how motor trend does top speed tests.
a fixed accurately measured distance covered in a given amount of time will give you your speed.

00 black/tan svt, #2052 of 2150, born 2/1/00 formerly known as my csvt "Nothing in the world is more dangerous than a sincere ignorance and conscientious stupidity." -Martin Luther King, Jr.