Cruise lights refer to lighting up just the corner modules or the whole lightbar, depending on the manufacturer, on a dim steady mode. They have many uses from letting residence know police are on patrol in the neighborhood, making easier to locate an officer for assistance, to being used when conducting investigations so the flashing lights aren't causing a lot of attention and disrupting peoples sleep.
Most LE vehicles have the function, but it's up to the officers to actually utilize them. Typically, the 4 corners of the lightbar are steadyburn on lowpower to show a LE presence (i.e. nighttime patrol) without lighting up the street unnecessarily. It's also great for nighttime use so that other responding units (if it's a silent approach) see your unit parked on the side of the road as they pull up
I guess it makes sense. I guessing they aren't used in my area. I don't know of any cars in our county nor any on my department that are used. They aren't even an option on our cars. Interesting how different agencies can be.
The only thing I have against LED's, is that they can be pretty much mounted anywhere, and requires self control on the part of person wanting them. I could never be an installer and light up a cruiser like a space ship.
When I see cruisers like that, I feel like there should be aliens chasing it down the street screaming for the mother ship.