Abstract: An emergency situation traffic signal control system, employing true radar and telemetry-based systems, which is a two-way, two frequency, full duplex transmission system. The system consists of an intersection transmitter/receiver electrically coupled to an intersection traffic signal control box and a vehicular transponder. The intersection transmitter/receiver generates an A/DCODE consisting of an access code ("ACODE") and a direction code ("DCODE"). The intersection transmitter/receiver continuously monitors the intersection by sending the A/DCODE signal in the approach directions relative to the intersection. An authorized emergency vehicle transponder approaching the intersection receives the A/DCODE, verifies the accuracy of the codes and re-transmits the DCODE, along with an optional vehicle identification code ("VID"), to the intersection transmitter/receiver for verification. If the vehicle is positively verified, control of the intersection is handed over to the vehicle by engaging valid preempt.
Type:
Grant
Filed:
June 29, 1990
Date of Patent:
January 21, 1992
Assignee:
Emergency Signal Systems, Inc.
Inventors:
Robert H. Brown, Charles R. Liebich, Gregory B. Page, Richard M. Scott