How exactly does he do so when there are several vehicles within the field of view of the radar beam??? - It goes directly against the training (which is well documented)... or are you saying the officer will lie under oath and say there was no other traffic and he got a steady tone and adequate tracking history (2-3 seconds = 300 ft+)...A pretty difficult feat on multiple cars with a limited sight distance....
Hint #2:
New York v. Olsen, 22 N.Y. 2d 230, 292, N.Y.S. 420, 239 N.E. 2d 354 (1968).
(Not that I agree with the Court's holding, but I know first hand that the traffic courts here still follow it).