Several theories attempt to explain why fire engines are red. One theory states that the majority of cars were black in the early 1920s, so fire engines were painted red to make them stand out from the other cars.
Another theory of why fire engines are red dates back to the 1800s. Red paint was the most expensive color available, and competing fire brigades used it to make their trucks stand out above their competitors.
While most fire engines are red, other colors are also used. Some cities have painted their fire engines yellow, white, blue, green or black instead of red.