Verified answer

When I rode with a county sheriff, his radar unit made noises that depended on the target car's speed relative to his car's speed. If the target car was going slower than him, it sounded like "ooooooooo". If the target car was going faster than him, it sounded like "eeeeeeeee". (The sounds are in addition to a digital readout that tells the exact speed of the target car.)

The sounds are not loud at all, a person standing outside of the car would be hard pressed to hear it. It would be impossible for the occupants of the target car to hear while driving down the road, even if the windows were down on both cars.

Radar is mounted to the dash of most patrol vehicles. and the speed is caught on a screen when the cop pushes a button after seeing 'enough' evidence of your speeding. Realize something; most cops have HUGE multi-tasking skills. As they drive they talk on the radio, use the mobile computer, watch for moving violations, wave, chew gum, listen to the stereo, all while thinking about the fasted route to the physical disturbance they are going to. And this goes on 6-8 hours on a 10 hour shift, every shift, for years and years . So, no it isn't any more dangerous than someone going more than 10 mph over the speed limit :) JUST kidding. Radar technology has vastly improved in recent years. Used to be the cop had to be following you. Now radar can track your oncoming speed as 81mph (wait for the math part),subtract the cop car speed (35) in the opposite direction and come up with 46 mph for YOUR actual speed!

sometimes they will beep after clocking your speed.

Yes

CHA-CHING $$