EMERGENCY VEHICLE CONTROL OF TRAFFIC SIGNALS

• US 3,638,179 A
• Filed: 04/16/1968
• Issued: 01/25/1972
• Est. Priority Date: 04/16/1968
• Status: Expired due to Term

• Current Assignee: Charles Grace, Edward T. Coll, Harold J. Braschwitz, Michael J. Manchester, Stephen A. Hunter III
• Original Assignee: Charles Grace, Edward T. Coll, Harold J. Braschwitz, Michael J. Manchester, Stephen A. Hunter III
• Inventors: Braschwitz, Harold J., Grace, Charles, Manchester, Michael J., Coll, Edward T., Hunter, Stephen A. III
• Primary Examiner(s): Cooper, William C.
• Application Number:
  US04/721,668
• Time in Patent Office: 1,379 Days
• Field of Search: 340/31-33
• US Class Current: 340/906
• CPC Class Codes: G08G 1/087 Override of traffic control, e.g. by signal transmitted by an emergency vehicle

Abstract

The present system provides a traffic light control system which enables an emergency vehicle such as a fire engine, ambulance or the like to control all traffic lights at each intersection through which it will pass in the course of its intended travel. The traffic lights can be rendered one green and three red at each said intersection along the route with the green light facing the oncoming emergency vehicle. In the alternative the system provides a means for rendering the traffic lights all red at each intersection thereby stopping the traffic in all directions and enabling the emergency vehicle to weave in and out of the stopped traffic.

Claims

1. In an arrangement of traffic lights having go, caution and stop lamps for directing the flow of vehicle traffic on streets and highways, an emergency regulating system for enabling an emergency vehicle to control said traffic lights comprising in combination:

first circuit means to receive a plurality of different direction-indicating direct-current signals, each of which is generated in response to direction-indicating signals transmitted from an emergency vehicle;

second circuit means connected to said first circuit means to receive said plurality of different direction-indicating direct-current signals, said second circuit means including a plurality of first type logical circuits each of which has a plurality of input channels and an output means and each of said first type logical circuits connected to receive a different one of said direction-indicating direct-current signals;

third circuit means interconnecting said plurality of first type logical circuits such that when any one of said first type logical circuits receives its associated direction-indicating direct-current signal said last-mentioned first type logical circuit will generate signals which will inhibit the remainder of said first type logical circuits from being response to their respective associated direction-indicating direct-current signals;

a plurality of second type logical circuits, each of said second type logical circuits having a plurality of input channels and an output means, each of said second type logical circuits connected to a different assigned one of said first type logical circuits to receive output signals therefrom and to generate first type control signals in response thereto;

go light timing circuit means for generating a second type control signal to inhibit said second type logical circuits from generating said first type control signals for a first predetermined time;

caution light timing circuit means for generating third type control signals for a second predetermined time, said caution light timing circuit means connected to said second type logical circuits to receive some of said first type control signals therefrom and to transmit at least one third type control signal to turn on at least some of said caution lamps for said second predetermined time;

fourth circuit means connected to said second type logical circuits and to said caution light timing circuit means to illuminate said go lamps and said stop lamps in a predetermined pattern, after said second predetermined time has elapsed, to accommodate an emergency vehicle whose related directionindicating signal is being processed by said first and second type logical circuits.

2. An emergency regulating system according to claim 1 wherein each of said second type logical circuits includes a memory circuit, each memory circuit being assigned to a different one of said direction-indicating signals to store an indication of the direction of the particular direction-indicating signal being processed.

3. An emergency regulating system according to claim 2 Wherein said caution light timing circuit means is connected to said second type logical circuits to erase from each of said memory circuits an indication of a previously received direction-indicating signal after said second predetermined time if such memory circuits were storing the same.

4. An emergency regulating system according to claim 1 wherein there are further included go lamp monitors connected to said go light timing circuit means to cause said go light timing circuit means to commence clocking said first predetermine time on each occasion that a go lamp is newly illuminated.

5. An emergency regulating system according to claim 1 wherein there is further included, at each traffic light location, a flasher lamp and wherein there is circuitry means connected from said second type logical circuits to said flasher lamp to cause said flasher lamp to flash in response to some of said first type control signals from said second type logical circuits.

6. An emergency regulating system according to claim 1 wherein there is further included a normal controller monitor circuit connected to said first type logical circuits which transmits a signal thereto to continually test whether or not said first type logical circuits are processing a direction-indicating signal and which acts to return said arrangement of traffic lights to a nonemergency mode of operation when said first type logical circuits are no longer processing a direction-indicating signal.

7. An emergency regulating system according to claim 1 wherein there is further included stop light monitoring circuit means connected to said second type logical circuits and to said caution light timing circuit to condition said second type logic circuits so that if a go lamp facing the emergency vehicle'"'"''"'"'s approach were illuminated it would remain illuminated and all other directions would have stop lamps illuminated and alternatively if a stop lamp facing the emergency vehicle'"'"''"'"'s approach were illuminated all directions would first be illuminated with a stop lamp and then said go lamp facing the said emergency vehicle'"'"''"'"'s approach would be illuminated.

8. An emergency regulating system according to claim 1 wherein there is further included a caution lamp control unit connected to said caution light timing circuit and wherein there is further included a stop lamp monitoring circuit means connected to said caution lamp control unit to condition said caution lamp control unit so that any caution lamps facing the direction where go lamps are illuminated at the time of an emergency are conditioned to be illuminated prior to their associated stop lamps becoming illuminated excepting if the illuminated go lamp is facing the emergency vehicle'"'"''"'"'s approach.