In this chapter, the wind mechanisms that induce vibrations in cantilever traffic
signal structures are introduced and the major research undertaken on vibration and
fatigue failure of cantilevered traffic signal structures is discussed. Some publications that
deal with the testing of damping devices are also briefly discussed, but only to cover the
aspect that deals with the vibration of mast arms. The damping devices themselves are
not discussed here since they fall outside the scope of this research.