Why do cops leave their lights on but not flashing?
Why do cops leave their lights on but not flashing? It's simple — police are letting you know that they're in the area. The lights on patrol cars are called “cruise lights” when they're not flashing, according to an old post from the Guilford Police Department, which notes that it's a common question the public asks.
What does it mean if a cop flashes his lights in front of you?
Usually when we do that we are trying to get your attention, so you pay attention to your driving; speed, lane usage, lack of attention, cell phone usage. Think of it as a warning. We may do this if your issue is not over the top, or perhaps we are on the way to another call and cannot stop you, but want to warn you.