Radar detectors are a good investment and will pay for themselves the first time they save your butt from a ticket. Speeding tickets run over $200.00 and a good radar detector is north of $600.00. But shop on E-bay and get a good used one for a 1/3 of the price. I try to stay just 5-7 mph over posted speeds on the interstate. I do 45 in a 45 and 35 in a 35. But when in a 55 mph zone I go a little faster and so on. But radar detectors of today can do alot for you.