Just got my 8500 x50. Couple of questions.

1) Should I turn x band on or off? When I got it, x band was off. And I just watched a video that says keeping x band off will prevent A LOT of false alarms. True?

2) For those of you on the east coast, I travel on Route 95 a lot. And one thing I'm noticing is that you will find a lot of cops hiding behind bridges waiting to get people. This leads me to a few questions.

a) How can a cop get your speed instantly from behind a bridge as soon as you pass them? What method is the officer using to catch people?
b) Lets say your driving down the highway and there is a bridge coming up in front of you.. If the cop isn't shooting his gun down the highway and he is just sitting behind the bridge waiting for people, will the detector pick up on it?

1. Where do you live? Is X band a threat?
2. Laser
a. Laser or instant on radar.
b. No, it's not a cop detector.