Gregory H Page

US Patent:

50831259, Jan 21, 1992

Filed:

Jun 29, 1990

Appl. No.:

7/546510

Inventors:

Robert H. Brown - Scottsdale AZ
Charles R. Liebich - Scottsdale AZ
Gregory B. Page - Gilbert AZ
Richard M. Scott - Chandler AZ

Assignee:

Emergency Signal Systems, Inc. - Scottsdale AZ

International Classification:

G08G 107

US Classification:

340906

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.