Do you think its ethical to make radar detections legal?

I dont know much about the radar detectors in cars that consumers can buy or if they are accurate but why is it legal in most states. Im going to ume they work. Why would the government make it legal for a driver to likes to speed be able to have a device that decreases the chance of getting a ticket. Sooner or later wont this speeding driver cause a damage to society of himself.