Can an officer search my car for a radar detector? I was stopped recently in Virginia for having a radar detector. The cop said he detected it on his radar detector. I pulled the detector down before he saw it. He had looked in a couple of cars before stopping me. At first I lied and said I didn’t have one but he saw the clip and I gave up and gave it to him. He asked to search the vehicle and I declined. If he had not seen the clip would I be required to have given up the detector and given him cause to search?

You’re right that in this situation, a police officer would need probable cause to be able to search your vehicle without your permission. Probable cause exists when the police officer has a reasonable basis for believing that a crime has been committed or is about to be committed. Your question really boils down to whether a Virginia court would see the police radar detector as reliable enough to result in the police officer reasonably believing that it accurately detected a detector in your car. Even if the detector isn’t actually reliable, as long as the officer reasonably believed in its reliability, he still would likely be able to search your car without permission. Assuming the detectors are fairly reliable, the police officer probably would have had probable cause to search your car without your permission.