Ok, when a cop is driving behind you, how can they tell your speed to any degree of accuracy? I’ve been trying to figure this out since I got a 50 in a 35 ticket. The deal is that my two tickets have been at the exact mph over the SL that nets me the next bracket of fine. (50 mph???)

So, a cop is following me. She can A) match speeds with me, but that has room for error not only in her judging my speed, but also reading her speedometer. (I believe’ we have Crown Victorias, and I don’t remember whether or not they have digital speedometers. Only rode in one once. Long story, no fault on my part.)

Or she could use a radar. My question is: Which would she use? And would the radar be affected by my own acceleration/deceleration at the time due to the compression of the waves of the radar?

(I probably won’t fight this. I just am tired of paying speeding tickets.)

If they were pacing you, then you have grounds to fight the higher fine. If they used radar, you are SOL. Cop radar is instantaneous, and it isn’t affected by your deceleration.

My advice would be to go to court and fight the fine. Plead guilty, but not to the higher speed, then ask for traffic school. Then learn to drive slower!

Oh, and since Q.E.D. hasn’t stopped by to ask me where I’m from, I’ll head him off and say Fayetteville, AR.

Cops who wish to have a “Pace” ticket hold up in court will have their Speedometer checked for accuracy and certified every coupld of months or so.

The radar works by reading both the relative speeds of both the road in front of the cruiser and the speed of your car. Then it does a little math to figure out the speed you’re actually going. If the road is going 50mph, and you’re going 5mph then it will read 55mph.

Also, I believe, there are better integrated units that will take info from the speedometer (again which is certified accurate) to calculate the speed you’re going, instead of taking two different radar readings.

Speaking strictly for PA, the methods commonly used are: Time and distance, where the police vehicle has a calibrated speedometer, and the officer follows you for several tenths of a mile at a given or greater speed (speed limit is 40, you were clocked at 52 and over three tenths, your speed increased to 54, so you were ticketed using 52), VASCAR, which is an electronic stopwatch used to compute speed between two known points of reference-typically white lines painted across the roadway (also regularly certified/calibrated for accuracy), and finally doppler radar.

Grr… I guess my only choice is defensive driving then. Oh well. (grumble grumble)

Realistically, about the only way tickets can be beaten is if the officer made an error on the citation (I beat one once because the registration was incorrectly copied and the listed reg came back not found on the MVR computer), had a speedo, vascar, or radar unit that was out of cal, or if the highway wasn’t marked in accordance with MUTCD (Manual on Uniform Traffic Control Devices). Signs must be a certain size, have a certain reflectivity, letters a certain size, spaced along the highway not further apart than x, and so forth. If you can prove that the area in which you were cited wasn’t properly marked, then the citation is invalid.

As the above are long shots but you’d like to save some points/money-request a hearing. Show up early and wait outside for the officer. Provided you weren’t a jerk when stopped, if you speak to him/her as a gentleman, and approach them with a ‘hat in your hand’ attitude, they will often respect your candor and reduce the listed speed in exchange for your guilty plea. Example: I was tagged years ago doing 88 in a 55 at 3 AM. I was nice, the trooper was nice-we were the only people on the road. I didn’t want the points, so I asked for a hearing, did just as I described above, and the trooper offered to reduce the charged speed to 67. We shook hands, I saved 3 points and about \$70.

I have very rarely(in fact I can’t remember a case but there must have been) been unwilling to recommend a lesser offense in court. The prosecutors are usually willing to give out no point tickets for guilty pleas. Even with DWIs you can usually get any lesser charges dropped as long as there is a guilty plea to the DWI. If you are willing to take the time to go to court it may save you some money in the long run. As for getting out of the ticket completely, probably not. The only way you could get out of it is if the speedometer was not calibrated properly. There are basically two ways to find out. Hire a lawyer and he will ask for discovery prior to the court date (of course that costs money). Or you can go to trial and have the officer produce the documents. If the officer is going around writing tickets using pace then most likely the car has been calibrated. Once you get to the trial there is no longer any chance of a plea bargain. You have to weigh the options for yourself.

Do be aware that there are specific instances where radar readings are not accurate: where there is another, large, vehicle (e.e. lorry or aircraft) passing. Basically, the radar bounces off your car, then off the lorry, then back to the detector, giving a false reading.