There’s a possible percent error even in perfect conditions but if cop was using radar and going in opposite direction then he prob did not evaluate the exact location for possible radar interference. That’s a possible variable for a small percent error. The fact you were both moving is a possible percent error. We’re you both at same elevation, hilly,....another possible percent error. Was it raining, windy with blowing rain or snow? Another possible percent error. These could be possible percent errors all concurrently and compounding, maybe leaving doubt you were going the speed as charged. All these variables exhausted when I defended myself in court and the prosecutor capitulated. Good luck. Even idlf only some of these variables existed it may be enough to present to prosecutor if you mention them that they may right off the bat make an offer of fine for non moving violation and no points. Good luck.
I tried that once in Germantown and managed to piss off the prosecutor and Judge. I still got the ticket.
I am an actual radar expert. The judge I had was unimpressed. I actually was not speeding (that time). When they want the money, they will get the money.
Every other time I’ve been ticketed I deserved it.
I helped a friend once with my expertise. The trooper, as it turned out, had the thickest glasses I’d ever seen on someone still allowed to drive when I met him before court. He didnt want to take a chance and asked the judge to dismiss.
So radar arguments have varying success.