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If I am stopped by a police officer with a radar gun. Can I ask him to show me the speed I was going on the radar? What are my options?

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fpressly
2154 Rider Driver
 Posted 1 week, 4 days ago

I live in South Carolina but go to Atlanta Georgia a lot. Atlanta has got to be the radar trap of the world. I have gotten at least a dozen speeding tickets over the years. How many have I been convicted of …ZERO! I got close one time, but that was because of a hard headed, biased judge. Let me share my secret.

In Atlanta they have many different methods for running radar traps. You have the lone officer (usually on a motorcycle) sitting on the side of the road zapping passers by and chasing them down to issue citations. Then you have the team approach. One or two officers operate the radar and several others on motorcycles give chase and issue the citations. Traffic is six lanes both ways and moving at a pretty good clip.

Let me begin by saying, in Georgia the officer is required to show you the radar gun if you request it (it may be different in your state). Certification and calibration records may be subpoenaed as evidence at trial. The showing of the radar gun is your first issue. In the multiple officer scenario, the office chasing you down does not have the radar gun with him and is therefore unable to show you. A fair judge who complies with the law rather than writing his own, would have to dismiss the ticket. It would probably be a good idea to make a discreet video or audio recording of your traffic stop. It will help when it comes to being your word against the officers. Many officers have body cams now which the video/audio can also be subpoenaed if necessary. If it is a single officer scenario I would still ask to see the radar gun as most of them are wireless and can be carried separate from the unit.

Now the real important part, if the above doesn’t bear fruit. I sent a FOIA demand to the Atlanta police department asking for a list of all the different radar units they use in the field. I then took that list and sent a request to the manufacturers of the various units to get user and maintenance manuals. I thoroughly read each manual front to back. They explained fully how the units were calibrated, when they had to be calibrated, covered certification issues and most importantly how to properly USE the radar gun to get a legitimate result. In doing so, I discovered a VERY IMPORTANT detail which has allowed me to beat countless tickets.

Police radar directly determines a vehicle’s speed by measuring the doppler (speed induced) shift of the return of its transmitted frequency (think of the sound you sometimes hear of an approaching or receding train or emergency vehicle). Police radar guns operate on three frequency bands: X-band, K-band, and Ka-band.

Most newer police radar guns operate on the super-wide Ka-band. K-band is still quite common, given its historical advantage to Ka-band. The oldest X-band radars, which have been widely used throughout the state of NJ, are slowly being supplemented with newer and smaller digital (DSP) Ka-band radar and even more lethal police laser guns.

Police radar transmissions are quite wide in their dispersion patterns and are often reflected in many directions. This gives a radar detector a lot of opportunities to detect the radar transmission and as a consequence generally provides the driver ample reaction time to slow down while vehicles ahead are being targeted.

Now here comes the important part. Per the manual, a “legal shoot” requires certain mathematical properties to be legitimate. First is the distance at which you are “shot” by the radar and second is the angle at which you are targeted.

Practically, the car has to approach or to move away within a specified angle aperture. The manuals for each of the radar explain what that angle is. Not necessarily directly on/from the gun, but somewhat so. The true velocity is the measured velocity times the cosine of the angle of the car’s direction of movement in relation to the gun. Direct approach is 0°/180°, the cosine of which is 1, so no correction necessary. at 90°, cosine is 0 and no speed is measured.

As long as the angle is known, the tangential component of the velocity (perpendicular to line-of-sight) can be calculated from the radial (towards/away-from) speed. With decreasing accuracy the closer the angle is to 90°.

In other words a car has to be at a certain angle from the radar operator to be a legit shoot. In six lanes of traffic the two outside lanes (slow lanes) are the most dangerous. The further you get to the inside lanes the safer you are. The officer must have clear line of sight acquisition without interference from other vehicles. The further you get to the inside lanes the closer you have to be for him to see you or else he is looking through/across 4–5 lanes of traffic. Imagine standing by the side of the road. You can look at cars on the inside lane directly across from you; but, the further up the road you go, the second, then third, then fourth, etc. lanes interfere with your line of sight. If the officer shoots you straight across the six lanes and tells you you are going 78 mph he is lying. Directly across from him, you are neither moving towards or away from him and the radar will read ZERO even if you are going 299 mph. Most radars work out to about 1000 yards. The angle of acquisition must be within a certain range of angle to be legit. 100% of the time, if you are on the inside three lanes, the distance and angle math coupled with the line of sight requirement are IMPOSSIBLE to achieve and therefore the radar evidence is inadmissible.

Now before you lay all this out to the judge you have to set the trap at trial. You have to ask the officer the details of the stop. What lane were you in, how far away were you, how heavy was traffic, did he rely solely on the radar gun for his report, was radar properly tested for calibration at the beginning of the shift, was the units annual certification done, what was the weather that day, where were you in relation to him when he zapped you? Given the fact that he/she has probably written hundreds of tickets, he may not remember if you didn’t show out and make him remember you.

Once you have established the proper groundwork, you then pull out the manual and explain to the judge why it would be impossible for the officer to have followed the manufacturers instructions and gotten a legitimate radar result. I can’t tell you how many times officers have stood on the side of the road and zapped me almost directly across the six lanes and claim you were speeding. You may have been; but, that radar unit couldn’t prove it. You have to go to great lengths setting up your case because most judges are very lenient with police and even will take their word that you were speeding just from observing you. The dirty ones will change your ticket from a say 85/65 to a “too fast for conditions” (with no specific speed claimed).

The fact of the matter is, most traffic courts are kangaroo courts. They are seen as revenue streams and everyone (judge, officers, prosecutors, even defense lawyers) are in on it. Oh they go through the motions; but, innocent until proven guilty is a fallacy. They all drink from the same pot of coffee in the back room.

If you are uncomfortable speaking in a court room by all means hire an attorney; but, let him in on the secret. Thanks for your upvote.

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