A crossbuck is a sign composed of two slats of wood or metal of equal length, fastened together on a pole in a saltire formation (resembling the letter X). Crossbucks usually are a traffic sign to indicate level railway crossings, sometimes supplemented by electrical warnings of flashing lights, a bell, or a gate that descends to block the road and prevent traffic from crossing the tracks.
In the United States, the crossbuck carries the words "RAIL" and "ROAD" on one arm and "CROSSING" on the other ("RAIL" and "ROAD" are separated by the "CROSSING" arm), in black text on a white background. Older variants simply used black and white paint; newer installations use a reflective white material with non-reflective lettering. Some antique U.S. crossbucks were painted in other color schemes, and used glass "cat's eye" reflectors on the letters to make them stand out. Other countries, such as China, also use this layout, but with appropriately localized terms. Often, a supplemental sign below the crossbuck indicates the number of tracks at the crossing.
A special kind of crossing sign assembly was introduced on an experimental basis in Ohio in 1992, the "Buckeye Crossbuck". It includes an enhanced crossbuck, reflective and with red lettering, and also a reflective plate reading "YIELD" below the crossbuck, whose sides are bent backwards in order to catch and reflect at a right angle the light of an approaching train. The experiment's final report gave the device a favorable review. However, the plate was rejected for inclusion in the 2003 Manual on Uniform Traffic Control Devices.
In Canada, crossbucks have a red border and no lettering. These were installed in the 1980s shortly after English-French bilingualism was made official, replacing signs of a style similar to those used in the U.S., except the word "RAILWAY" was used instead of "RAILROAD".
In Mexico, the crossbucks read "CRUCERO FERROCARRIL", a literal translation of its U.S. counterpart. Older designs read "CUIDADO CON EL TREN", meaning "beware of the train". In Argentina, the most common legend is "PELIGRO FERROCARRIL" ("danger: railroad"). Earlier crosses also read "CUIDADO CON LOS TRENES - PARE MIRE ESCUCHE ("beware of the trains - stop, look, listen")