I almost never use mine in the city...very rarely speed in city limits and the constant warnings get annoying

On the highway, exactly what Gary said...wait for somebody in a hurry and follow a few hundred metres behind. Drove to/from chicago last year and it saved me at least one ticket when the speed limit went from 100 to 80 just outside of winnipeg. Picked up the warning off the poor bugger ahead of me that got pulled over.

the only ticket ive ever gotten was ironicly enough when i had the radar detector going and got nabbed by laser taking my motherinlaw to the airport when she was late for her flight back home.