3M Innovative Properties Company

L & H Company, Inc.

Gary V Jones

Kevin Judge

James C Beck

Richard Keegan

Richard Gerald Keegan

Ronald R Hatch

James R Hume

For qualification for traffic preemption an area is defined and if the vehicle is in the area it can obtain preemption. The vehicle's position is determined, in one embodiment, by use of differential GPS.

Automatic determination of traffic signal preemption using GPS, apparatus and method

Automatic determination of traffic signal preemption using GPS,

A traffic signal preemption system, and a related method for its use, using differential global positioning system (GPS) measurements for accurate monitoring of the position, speed and direction of an emergency or service vehicle approaching a controlled intersection. The preemption system includes a reference GPS receiver, for computing GPS measurement corrections, and a GPS receiver in each vehicle, which transmits its GPS measurements by radio to a receiver located at the controlled intersection. A computer also located at the intersection uses corrected vehicle position, speed and direction measurements, in conjunction with previously recorded data defining approach routes to the intersection, to determine the optimum time to switch a traffic light controller to preemption mode to permit safe passage of the vehicle. GPS measurement corrections may be applied in a vehicle computer or in the computer located at the intersection. Other modes of operation of the system include a self-survey mode, whereby the reference GPS receiver determines its own true position by averaging position measurements over a period of a day or two, and a learn mode, whereby the intersection computer 'learns' unusual approach routes to the intersection as the vehicle traverses the approach routes and transmits position and velocity measurements.

Automatic determination of traffic signal preemption using differential

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Bolingbrook, IL, United States of America

Gary V Jones