Why Are Most Police Lights Red and Blue?

Police lights are commonly accepted to be red and blue. We are used to seeing red and blue LED light bars for police cars, but have you ever wondered why these colors are used for police lights?

Color Associations and Caution Light Bar

We all associate colors with certain things, even if we don't realize we are doing so. Color theory is a scientific field aimed at understanding how to use color to control emotions, influence our decision-making processes, and provide information to us.

You can see color theory applied to all aspects of life, even in the design of simple product labels. It's no surprise, then, that color theory is also applied when choosing colors of police vehicle warning beacons.

In nature, red is a warning color. We are programmed to react when we see red, which is why stop signs are red, for example. Red is a color of alertness, awareness, attention, and caution, which is exactly what police cars want people to do when they see police lights.

After all, police lights and sirens are all about alerting. They're about notifying other road users of potential problems. Red is a natural choice for police lights because it's a warning color that nature has chosen, and all police car light bars are doing is tapping into the part of our brains that has long associated red with danger.

Is that it, then? Red is a color that we all respond to, a color that makes us cautious, so police lights use this known reality of color theory to remind the public of their presence.

Police Lights and Brake Lights

The impact of red on the human brain should not be underestimated. It's used time and time again to try and provide warnings and remind us of potential dangers. Unfortunately, this is something that all car manufacturers understand, which is why brake lights are also red.

Their logic is easy to understand. As we discussed, red is the natural "stop" color. It's the color we should all pay attention to, and there are many situations on the road where we need to be attentive, such as when the vehicle in front of us is braking. To draw attention to such an event, the brake lights on most vehicles are red, making them quickly noticeable and inviting a prompt reaction. Likewise, the red color employed in safety car lights ensures that other road users can quickly identify and respond to a potential hazard.

This works fine by itself, but when combined with police lights that are also red, it becomes a problem. Two different functions, police car perception and other vehicle braking warnings, are essentially using the same tool to achieve their goals. As a result, they compete for attention. Red is no longer the primary, shocking color it should be; it has essentially become a popular color used to grab attention, and it's been overused.

Police cars have solved this problem by now commonly using blue light bars to replace or supplement red lights.

Blue is the chosen color for police lights because there are hardly any other blue lights on the road. Headlights are yellow and white; brake lights are red, but blue is not visible. Therefore, blue is able to stand out and provide the differentiation that police cars need.

Due to the brake light issue, police cars often alternate between red and blue lights. This helps to provide the "shock" of red, but also makes the vehicle stand out amidst a sea of red brake lights, considering that most civilians are not allowed to use police flashing lights.