GB1315525A - Traffic signal remote control system - Google Patents

Abstract

1315525 Photo-electric control MINNESOTA MINING & MFG CO 14 May 1970 23446/70 Heading G1A [Also in Division G4] In a traffic control system, for a street intersection, a photo-electric detector receives pulsed light signals transmitted by an emergency vehicle approaching the intersection, which cause the traffic signal to indicate "Stop" in the cross street direction and "Go"in the direction of travel. For each street a photo-electric detector 36a, 36b Fig. 5 (not shown) is associated with each direction of travel, the detectors being connected in parallel and shunted by aninductance (37) to form a tuned circuit responsive to the pulsed light but not to steady ambient light. The traffic lights 11a are cycled by the control box 11b controlled from detector, 12b, which receives the signals emitted by the transmitter, 12a mounted on the vehicle 10. The transmitter consists of a lamp, 16, which provides pulsed, high intensity light, either visible or infra-red. The phase selector control unit, 35, then sends on a rapidly pulsed signal to step on the controller 11b so that a green traffic signal is produced along the street along which the vehicle crosses the intersection. Simultaneously, an emergency vehicle travelling towards the intersection along another street is prevented from affecting the signalling system. The actuator, 62, in 35, Fig.7 (not shown) applies a pulse series to relay 66 and a faster timing is substituted for the normal rate, the timing cycle is reduced, and the required green light is obtained earlier.