Some LEO wrote this..
Radar Detector and Laser Detector Facts
There are many, many myths and misconceptions floating around out there about RADAR (Radio Detection And Ranging) and LASER (LIDAR or LIght Detection And Ranging) units and how they operate to determine who gets a speeding ticket. As a certified RADAR/LIDAR instructor, I can tell you that your best bet, regardless of what you choose to believe, is to just drive the speed limit. No matter who believes what about the reliability of the equipment and/or the competence of the officer using it, the only way to eliminate all doubt is to obey the law. These are the most common comments I have heard over the years concerning this topic. I do not consider myself to be an "expert" in the workings of all RADAR/LIDAR equipment on the market. I simply want to provide you with the best information I can to allow you to make an educated decision on what you do out on the road.
"RADAR won't work in bad weather". False. RADAR "accuracy" is generally not affected by inclement weather, however the sensitivity may be diminished somewhat. The main reason that you do not see many tickets being written in bad weather? Cops do not like to be out in the elements any more than anyone else.
"RADAR DETECTORS will prevent me from getting a speeding ticket". No, you driving the speed limit will prevent you from getting a speeding ticket. I think I have defeated about every kind of RADAR detector on the market. They are okay as a tool to help keep you alert (maybe) but they are not very effective as a tool to keep you from getting nailed with the RADAR gun. Nearly every RADAR unit on the market today has a "hold" feature which allows the officer to prevent the RADAR beam from leaving the unit until he/she wants to check the speed of a vehicle. It is very common for the beam to be released, a speed obtained, the speed locked in, and the beam held again all within a matter of a second or two. That is much faster than you can react to your radar detector, brake, and get your car slowed down enough to avoid being stopped. In fact, the majority of detectors cannot even be activated in that short time. So, if the officer is using the unit to its full potential, you'll get nailed every time. Radar Detectors are also illegal in some jurisdictions and most can be detected by a radar detector detector. Currently only the Beltronics STi unit is shielded. Clcik on the radar detector recommendations link below to see the Beltronics unit.