I think that's called VASCAR. It can be done with ANY two points. A couple of light posts, two trees, mailboxes, etc. In most states, if the arresting officer (guy that actually pulled you over) is not the same guy that did the "measuring", you can claim that they got the wrong guy. A mis-communication between the officers. (Same thing with "bear in the air" arrests.) Also, if there were any obstructions between you and him at ANY point in the arrest, you can question how he saw you commit the crime.* Most cops don't even show up to defend VASCAR tickets, because most get thrown out because the burden of proof is on them. If they do show up, the guy that pulled you over is going to show up because he wrote the ticket. It is very likely that he never WITNESSED you speeding. The guy that did simply radioed the description of your car to the other. That's another reason they get thrown out. They won't send the other cop 1) they have too much time tied up in something they can't win 2) not very many officers qualified to do their business in the air, they need him there. Not in a court-room.
*-If you are speeding, and the officer does get you on something "foolproof", you'll notice that the officer will look right at you when turning around or before pulling out. The reason they do this is because if asked in court if the person that they witnessed speeding is in the room, they can assuredly say "Yes". They are collecting a physical description of the operator. Saying "It was a guy in a red Mustang" is just not good enough.
