Best Radar DetectorsBest Overall:Best Long Range:Best Filtering:Best Value:Most Compact:The Expert: I’ve spent more than three decades testing car electronics, and have used radar detectors since the mid-90s. I coordinated a radar detector shootout as editor of Car Audio & Electronics for many years, and have tested radar detectors for Popular Mechanics for the last three years. Where Radar Detectors Are IllegalRadar detectors are legal in most states, but not all. What to ConsiderHow Radar Detectors WorkRadar detectors sniff out radar and laser signals operated by law enforcement to measure a vehicle’s speed. All radar detectors have a mute button to manually silence false alerts and mark locations that cause frequent false alerts.