How accurate are radar devices?

On Behalf of | Apr 20, 2020 | Criminal Defense

Few things likely frustrate you more than receiving a speeding ticket when you know you were at, but not above, the speed limit. But what should you do? Argue with the officer? This probably will not get you anywhere. After all, (s)he had his or her radar gun pointed at you, and it said you were speeding. 

FindLaw recommends that in a situation like this, your best course of action consists of challenging the radar evidence in court. However, you and your attorney need to do your homework first. 


What most people fail to realize is that any radar device requires frequent calibration. Once you and your attorney discover which radar device the officer used, you can probably find the instruction manual issued by its manufacturer online. It should contain specific instructions not only on how often the device needs calibration, but also how the officer should perform that calibration. 

Most manufacturers recommend device calibration before each usage. Did the officer do this before using his or her device on you? Furthermore, most instruction manuals specify the type of tuning fork that the officer must use in order to properly calibrate the device. Did the officer use this tuning fork? If not, the reading could be inaccurate. 


Proper training represents the second prong of radar device accuracy. If the officer failed to receive the manufacturer’s recommended training course, (s)he could have used the device in an improper way. (S)he also could have inadvertently misread the speed it showed you going. 

Bottom line, radar devices are not infallible. Both the device itself and the officer wielding it must be working properly to ensure accurate results.