The traffic signal controller is the equipment (including the housing) that switches power to the signal lanterns and controls the duration and sequence of signal displays. This equipment is placed in a ground-mounted housing or a post-mounted housing. Further guidance on the electrical design of traffic signals is provided in Appendix F.
Figure 6.12 illustrates how the controller interfaces to the other components of the signal system. The physical characteristics of the controller are specified in AS 2578.