In a sense, yes. Yes, for instance, you see a car enter an interstate. He's hauling and you know it. You speed up to close the distance and attempt to get a speed reading. Pacing is out. His speed is "X". Your speed is X + Y. You HAVE to tell the radar that your speed is greater than the target speed or you will get a false reading. You hold the "slower" button to do this. Now, do you hold it the entire time? No. As you approach, you hit the button, get the target speed, and that is the speed you use to write the ticket, or whatever. You do not have to constantly measure his speed during the run down, one "hit" is enough. That "hit" usually comes when you are closing within range of the unit (which varies due to weather conditions). radar will work in the rain but the range is limited. I chose not to enforce a whole lot of speed in the rain.