Systems and method for controlling preemption of a traffic signal
A priority control unit is provided for use with light-based and GPS-based traffic control priority systems. The priority control unit includes a light emitter subsystem that is configured to emit pulses of light. The pulses of light encode a priority request for activating preemption of a traffic signal by a light-based traffic control priority system. The priority control unit also includes a GPS-based subsystem that is configured to transmit a priority request by radio waves. The priority request from the GPS-based subsystem is for activating preemption of a traffic signal by a GPS-based traffic control priority system. A switch is coupled to the light emitter subsystem and to the GPS-based subsystem. The switch simultaneously activates both the light emitter subsystem and the GPS-based subsystem for transmitting priority requests in response to user control. In another embodiment, the priority control unit further includes a broadcast based subsystem for transmitting priority requests.
1. A priority control unit for use with light-based and GPS-based traffic control priority systems, wherein the light-based traffic control priority system activates preemption of a traffic signal in response to pulses of light encoding a priority request, and the GPS-based traffic control priority system activates preemption of a traffic signal in response to a radio signal encoding a priority request, comprising:
a light emitter subsystem configured to emit pulses of light that encode a priority request for activating preemption of a traffic signal by the light-based traffic control priority system;
a GPS-based subsystem configured to transmit a priority request by radio waves, the priority request for activating preemption of a traffic signal by the GPS-based traffic control priority system;
a shared communications bus coupled to the light emitter subsystem and to the GPS-based subsystem; and
a switch coupled to the light emitter subsystem and to the GPS-based subsystem, wherein the switch simultaneously activates both the light emitter subsystem and the GPS-based subsystem for transmitting priority requests in response to user control.
2. The priority control unit of claim 1 , further comprising:
a broadcast subsystem that transmits a priority request to a centralized control system; and
wherein the switch is coupled to the broadcast subsystem and simultaneously activates the broadcast subsystem with the light emitter subsystem and the GPS-based subsystem.
3. The priority control unit of claim 1 , wherein the light emitter subsystem and the GPS-based subsystem are configurable via the shared communications bus.
4. The priority control unit of claim 1 , wherein:
the light emitter subsystem and the GPS-based subsystem are configurable with respective identifier codes via the shared communications bus; and
the light emitter subsystem and the GPS-based subsystem transmit the respective identifier codes in respective priority requests.
5. The priority control unit of claim 1 , further comprising:
a broadcast subsystem coupled to the shared communication bus and configured to transmit a priority request to a centralized control system;
wherein the switch is coupled to the broadcast subsystem and simultaneously activates the broadcast subsystem with the light emitter subsystem and the GPS-based subsystem.
6. The priority control unit of claim 5 , wherein:
the light emitter subsystem, the GPS-based subsystem, and the broadcast subsystem are configurable with respective identifier codes via the shared communications bus; and
the light emitter subsystem, the GPS-based subsystem, and the broadcast subsystem transmit the respective identifier codes in respective priority requests.
7. The priority control unit of claim 1 , wherein the light emitter subsystem includes a plurality of LEDs.
8. The priority control unit of claim 7 , wherein the LEDs are infrared LEDs.
9. The priority control unit of claim 7 , wherein the LEDs include a plurality of visible light LEDs and a plurality of infrared LEDs.
10. The priority control unit of claim 1 , wherein the light-based traffic control priority system includes a receiver with a photodetector and circuitry that produces a number of electrical pulses in response to each detected light pulse, wherein for each detected light pulse the number of electrical pulses represents a level of radiant power of the light pulse, and a threshold number of electrical pulses and an activation frequency at which the threshold number of electrical pulses is repeated activates preemption, further comprising:
wherein the light emitter subsystem includes:
a light emitter; and
control circuitry coupled to the light emitter and controlling the light emitter to emit bursts of light pulses, wherein each burst includes at least two light pulses and a frequency of light pulses in each burst and a frequency of the bursts cause the receiver to produce at least the threshold number of electrical pulses at the activation frequency and activate the preemption.
11. A method for generating priority requests to light-based and GPS-based traffic control priority systems, wherein the light-based traffic control priority system activates preemption of a traffic signal in response to pulses of light encoding a priority request, and the GPS-based traffic control priority system activates preemption of a traffic signal in response to a radio signal encoding a priority request, comprising:
simultaneously activating both a light emitter subsystem and a GPS-based subsystem in response to a single user control;
emitting pulses of light by the light emitter subsystem, the pulses of light encoding a priority request for activating preemption of a traffic signal by the light-based traffic control priority system;
transmitting a priority request via radio waves by the GPS-based subsystem, the priority request for activating preemption of a traffic signal by the GPS-based traffic control priority system; and
configuring the light emitter subsystem and the GPS-based subsystem via a shared communications bus that is coupled to the light emitter subsystem and to the GPS-based subsystem.
12. The method of claim 11 , further comprising:
simultaneous with activating the light emitter subsystem and the GPS-based subsystem, activating a broadcast-based subsystem; and
transmitting a priority request by the broadcast-based subsystem.
13. The method of claim 11 , further comprising:
wherein the light emitter subsystem and the GPS-based subsystem are configurable with respective identifier codes via the shared communications bus; and
transmitting the respective identifier codes in respective priority requests from the light emitter subsystem and the GPS-based subsystem.
14. A system for generating priority requests to light-based and GPS-based traffic control priority systems, wherein the light-based traffic control priority system activates preemption of a traffic signal in response to pulses of light encoding a priority request, and the GPS-based traffic control priority system activates preemption of a traffic signal in response to a radio signal encoding a priority request, comprising:
means for simultaneously activating both a light emitter subsystem and a GPS-based subsystem in response to a single user control;
means for emitting pulses of light by the light emitter subsystem, the pulses of light encoding a priority request for activating preemption of a traffic signal by the light-based traffic control priority system;
means for transmitting a priority request via radio waves by the GPS-based subsystem, the priority request for activating preemption of a traffic signal by the GPS-based traffic control priority system; and
a shared communications bus coupled to the light emitter subsystem and to the GPS-based subsystem.
15. The system of claim 14 , further comprising:
wherein the means for simultaneously activating both the light emitter subsystem and the GPS-based subsystem includes means for simultaneously activating a broadcast subsystem along with the light emitter subsystem and the GPS-based subsystem;
means for transmitting a priority request by the broadcast subsystem to a centralized control system.