Legal How-To: Challenging Radar Guns in Court - Law and Daily Life
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Legal How-To: Challenging Radar Guns in Court

Fighting a speeding ticket when the officer uses a radar gun is difficult, but not impossible. As with other instruments like Breathalyzers, a radar gun is not without its potential flaws.

Here are three possible ways you may be able to challenge radar gun evidence in court:

1. Request a Calibration Record.

Like Breathalyzers and other automated devices which law enforcement use, radar guns must be calibrated in order to have their readings accurately reflect the actual speed of a vehicle.

If the officer cannot provide the record for calibrating the radar gun within the recommended time frame (usually 30 to 60 days), then you may be able to argue that the evidence based on the gun is unreliable.

Since the radar gun is likely to be the only evidence of your speeding offense, a judge could potentially toss the case if the officer cannot prove the instrument was properly calibrated at the time of your citation.

2. Challenge the Officer's Training.

The officer who cited you for speeding needs to have some amount of training with the radar or LiDAR gun in order to operate it and obtain an accurate estimation of your speed.

Similar to the argument about calibration, a judge may toss evidence from an officer who was not properly trained to use the LiDAR or radar gun which "clocked" your speed.

3. Make a General Hearsay Objection.

Similar to how you might fight a red-light camera ticket, you can try to argue that the evidence based on a radar gun reading is pure hearsay, and there is no admissible evidence to show that you were speeding.

Hearsay evidence from computerized devices is often offered on the grounds that it has been proven reliable. But the "confrontation clause" of the U.S. Constitution requires that you be allowed to cross-examine the witnesses against you. So if other officers or technicians were responsible for calibrating the device, you may argue that you have a constitutional right to examine those witnesses.

An officer may, based on his or her training and experience, estimate using his or her sight how fast you were going. But if the officer was relying solely on a radar gun, this may be a good option.

Need More Help?

Don't feel intimidated by cops with radar guns, especially if you know you weren't speeding. For more specific guidance on how to challenge radar guns in court, you may want to consult an experienced traffic attorney near you.

Are you facing a legal issue you'd like to handle on your own? Suggest a topic for our Legal How-To series by sending us a tweet @FindLawConsumer with the hashtag #HowTo.

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