True story
Traffic cop giving evidence during a trial of a man accused of speeding.
Defence lawyer asks how the traffic cop could be certain that the accused's vehicle was travelling at more than 30 mph.
Cop replies that given his 30+ years as a driver, his 20+ years as a Police Officer and his 12+ years as a traffic officer, having gained all the qualifications that goes along with that, that in his opinion the vehicle was travelling well in excess of the speed limit.
Lawyer says, so its all about your opinion then, Cope replies yes sir.
Lawyer then throws a pen across the room and asks, Constable, in your opinion, how fast was that pen travelling.
I have no idea sir replies the officer.
But, Constable, you have just told us all about your experience of speed estimation, so how fast do you estimate the pen was travelling at?
I have no idea sir.
Why is that Constable.
Well sir, I have never driven a pen.