several things need to be discerned before you react.
Are radar detectors legal in your area? Many US places have made them naughty objects but the truth still is, they work. it is like a flashlight, the beam of light is detectable much further way than the light beam can see.
Second, jammers. This is usually highly illegal and not so good of an idea, but very easy to do. If you can find out the frequency on which your local police radar operates, then making a radio transmitter that can transmit signals on the precise frequency that simulates the reflected waves at say ten miles an hour, is something any first year tech school kid should be able to make. Another is a transmitter that blasts out the same frequency at rapidly varying modulation thus preventing the cops radar from getting a "lock" on your car. When speed was a big thing in my life, i used a jammer, I often got stopped after blasting thru a speed trap at 80 mph and the officers radar gun reading 33 mph. I never got a ticket either. Nowadays, I think a smart kid could hook up a radar detector to a jammer box and get the jammer to trigger on and off in relation to the presence of appropriate radar waves.