Ok guys heres the deal on this hole radar thing. LEO'S have a couple of different options to choose from I.E. Roving radar, stationary radar, LIDAR, pacing, and an Air Unit.
First off the Roving Radar - Its set up on the dash of the police car or police Motor cycle. It uses an antenna in the front and rear of the unit. The cop has a control box in the car when he is driving around it is on stand by, when he observes a vehicle he is supposed to estimate his speed, I.E. 67MPH then he has to hit the button on the radar to clock the vehicle. When the radar is on stand by the detector will not pick up the radar beam making it detector go off and alert you, Only when he hits the button to clock you will it go off and tell you hey theres a cop, and by then its to late hes already got you when he hit the button.
Stationary radar - it uses the same principle as roving but the cop must be stationery. It's typically a hand held gun instead of being mounted in a vehicle.
LIDAR - it's a hand held gun that limits a laser beam to judge speed and distance, the officer can pick out a vehicle from a pack the this vs a regular radar unit that just emits a cone shape beam. As for the hole laser jammer or diffusers, I have yet to see one actually work for the fact lets just say you have it installed on the front bumper of your car where the front fangs are. The LIDAR has gun sight optic that he can aim and pinpoint any part of your Car I.E. your rear view mirror or roof of your car. for the jammer to even remotely work the cop would have to aim it directly at the jammer it self.
Pacing - lets say you're driving down the road at 90MPH and you are so concentrated on the fact you're cursing down the road or paying attention to the chick in the passenger seat that you did not notice that cope that got o the highway as you were passing an entrance ramp. he see you pulling away from him he catches up and PACES you going 90MPH thats all he needs to give you a ticket.
Air Unit - or helicopter. some agency have them and what they do is hover high up and look down to the markers they have already set up most of the time they are white X shapes on the side of the highway as you pass the markers the will start a stop watch and then stop the watch as you pass the next marker about a mile down the road or so. Then they take your time and do a math formula and boom they now have how fast you were going. And then radio your vehicle color and make to the cops that are a couple of miles down the road.
Now all of that being said radar detectors are not a total waist of money, you could get lucky and it might pick up on a beam that a cop shot at another car a little bit up the road. But I would not put your faith in one that it will not let you get a ticket. Just some food for thought For my fellow Z brothers. And incase you were wondering I have been a cop for a number of years now.