Red and Blue
The instantly recognizable sign of a police vehicle in North America. Red and Blue lights have been used commonly for the last 30 years in North America to signify police vehicles. But is there a danger to using Red and Blue together? I believe that the use of Red and Blue lights in combination actually introduces further danger to the Police then the benefit of being able to distinguish police vehicles from other emergency response vehicles. With LED lights becoming more popular these days, this is a concern that is becoming more and more serious all the time. LED's have a very narrow light spectrum and thus achieve VERY Red and VERY Blue colors. LED's are also very bright, which is good to an extent. The bad part of them being bright, is that when you mix Red and Blue, the eye has to work very hard to be able to focus on them. The problem is that the human eye has trouble focusing on the colors Red and Blue, at the same time (try looking at a red and blue neon sign at night from a distance). At night especially, it is very difficult for the human eye to correctly focus on the scene ahead, when Red and Blue lights are present next to eachother. If a driver approaching a scene has issues focusing on what is going on at the scene, the scene becomes distracting. The chances that the driver will try to focus on the lights / scene long enough for him to loose concentration on where he is driving is increased. And thusly I am going to predict that Police Vehicles with red and blue lights have been involved in more rear end, on scene collisions then police vehicles with solid red or solid blue lights. I am going to guess that this has never been studied before, but this is my challenge to anyone able to conduct such a study... I believe there are some colors which will work better together. Blue and Yellow work alright, as does Red and Amber... and Blue and Green work alright as well. I urge all police departments to look into this issue. I think that even Red / White (limited white lights, not too many) will be more effective to the rear of a police vehicle then Red / Blue. As for the front of a police car, Red and Blue is still viable. My concern is mainly with the rear, and traffic approaching a scene.