Originally Posted by
DrIsotope
It should be good enough for your purposes-- provided you can set up in a spot close enough. Consumer radar guns are mostly used for baseball, and therefore have a limited range-- they only need to measure about 100'.
Myself, I would just put two marks on the ground a known distance apart, and set up a camera. Nothing is as accurate as time over distance.
True. But there is a reason why those white marks on highways are usually 1/4 mile apart - the longer the distance, the more accurate the measurement. Since I doubt the OP has an aircraft, the distance would be so short as to make it pretty inaccurate, I'll bet.