Not if the cop is looking for approaching vehicles which are speeding. My brother used to be a police officer in a very small town in New Hampshire. He would cruise down the highway checking the speed of oncoming vehicles. If someone rocketed past him, he’d do a youie, chase the guy down and cite him.
You can’t do that without a radar gun.
One more thing. This is my basic understanding of how radar guns handle the issue of movement of the officer’s car.
The gun is NOT wired into the speedometer of the officer’s car. Instead, the gun actually fires two beams. One beam is meant to hit you, and the other beam is meant to hit a roadside (i.e. stationary) object. The beam that hits the stationary object ends up measuring the speed of the officer’s car, and then that speed is used to offset the speed measured by your vehicle.
Now, the problem is… what if the beam that’s supposed to hit a stationary object hits something that’s moving? Well, odds are that it will lower the speed of the officer’s vehicle (because it’s probably hitting something going in the same direction as the officer) and your speed will look MUCH higher.
How does the officer know what’s going on? Well, the radar gun has two numbers that show up, one is for you and the other is the officer’s speed. He should make sure that his speed on the speedometer matches that on the radar gun.
I’m not sure if any of this matters to you if/when you go to court to fight the ticket. Even if the officer didn’t check the speeds and they were actually off, I have no idea of how you would prove. Yes, I know that the officer is supposed to prove you were guilty, and not the other way around… However, it never seems to actually work that way in traffic court.
Brian