Red and blue lights are used on U.S. police cars for many reasons, but the main one is that they are highly visible and easily distinguishable from one another.

Blue and red lights also can stand out, regardless of the time of day. Because blue is a fairly unique color to see in our natural world (besides a blue sky), it can stand out during the daylight.

HOUSTON (CW39) – The sight of blue police lights is a common yet powerful symbol in modern society. These lights are not only a tool for law enforcement but also serve as an important signal … ...

Red and blue lights are used on U.S. police cars for many reasons, but the main one is that they are highly visible and easily distinguishable from one another.