Patent ID: 7423551

Claim:
A portable traffic signal system operable for use at the same location as a permanent traffic signal system, said permanent traffic signal system comprising permanently mounted electrically operated signals for controlling traffic and a permanently mounted system controller which generates a predetermined sequence of operation for said permanently mounted electrically operated signals, said permanent traffic signal system being subject to outages, said portable traffic signal system comprising: portable electrically operated signals to be displayed for controlling said traffic, said portable electrically operated signals being configured for use at a selectable location; a portable power supply to operate said portable electrically operated signals; a portable system controller operable for controlling said electrically operated signals to be displayed; one or more timing mechanisms for generating a predetermined timing sequence to control a sequence of operation of said portable electrically operated signals to be displayed; an interface for sensing operation and outage of said permanently mounted electrically operated signals and for producing external control data in response to said operation or outage of said permanently mounted electrically operated signals; and a receiver for receiving external control data, when said external control data is present then said portable system controller being configured to respond to receipt of said external control data in at least one of a first mode of operation wherein operation of said portable electrically operated signals is at least partially inhibited and a second mode of operation wherein operation of said portable electrically operated signals is synchronized with said permanently mounted electrically operated signals, and wherein when said external control data is absent then said portable system controller is configured to utilize said predetermined timing sequence generated by said one or more timing mechanisms for controlling said portable electrically operated signals.