Do they work??? OH yeah they work but different brands work with different signals. I have a Passport 8500 I love it, It beeps when I drive by automatic doors and stuff just have to get use to it. It got me out of 3 tickets with plenty of early warning.
only works if there is other traffic, But lets say for instance you are on a stretch of highway and you are the only 1 on it, radar detector is useless unless the cop had left his radar on. But most have instant on, and it to late.02
They work in variing degrees. Instant on Radar will defeat your detector unless the officer is not pointing it at you. A quality radar jammer will work against instant on, but I do believe you pay a hefty price if they detect it in some unrelated stop. In Europe they are illegal, but only if they can prove you were using it to defeat traffic enforcement..go figure that one.