In the past fire departments used to compete to be the first on a fire scene. At the time red was the most expensive color so by painting your fire wagon red you were implying that you were better than the rest. That became the tradition. In the late 60s and early 70s there was an increase in the number of cars running into the back of fire trucks at night. This seemed only natural since most people who are color blind, are red color blind, and could not see the fire engine on the roadway. Many fire departments changed the color of their trucks to yellow since that is the most visible color to the human eye in an attempt to decrease the number of accidents. In the end the change in color did decrease the number of accidents and some fire departments went back to the traditional red color. Klein choose not to and stuck with the yellow-green color to set us apart. Today you can see fire trucks painted all different colors.