Abstract: A coordinator for a traffic signal controller having a motor and associated switching system for establishing the duty and width cycle of the controller. The controller being connected, via electrical circuitry, to an AC power grid. The coordinator is a self-contained unit arranged for connection to the controller to effect coordination thereof by producing timing signals in response to receipt of either AC signals from the electrical circuitry or stray AC radiation from adjacent sections of the power grid. The coordinator also includes an independent oscillator for producing independent timing signals. Thus, the coordinator can maintain coordination of the controller under normal operating conditions or under the abnormal operating conditions of a local power failure or a general power failure.