System and method for transmitting data in an optical traffic preemption system

Abstract From the Canadian patent

An optical data communication system for transmitting a stream of light pulses, including both priority pulses and variable data pulses from an optical emitter atop certain vehicles, such as police cars, etc. to a detector mounted along a traffic route. The method allows variable data to be transmitted in a stream of light pulses along with priority pulses. The variable data can include an identification code that uniquely identifies the emitter an offset code that causes a phase selector to create a traffic signal offset, an operation code that causes traffic signal lights to assume at least one phase and a, range setting code that causes a phase selector to set a threshold to which future …