Remote control system for traffic signal control system

• US 4,162,477 A
• Filed: 06/03/1977
• Issued: 07/24/1979
• Est. Priority Date: 06/03/1977
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Munkberg, John A.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Groody, James J.
• Application Number:
  US05/803,037
• Time in Patent Office: 781 Days
• Field of Search: 340/32, 340/33, 340/34, 340/40, 340/36, 340/147 LP, 328/72, 250/199
• 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

A multiple priority remote control system for the remote control of a traffic signal control system for a traffic intersection responsive to optical signals transmitted by optical energy transmitters carried on designated vehicles operating along the roadways of the intersection. The remote control system includes signal discriminator circuitry for producing high or low control signals dependent upon the particular optical signal that is detected and in accordance with the roadway of the intersection from which the detected optical signal is received. A control circuit connected to the controller for the traffic signal control system and to the discriminator circuitry responses to the control signals to provide a green light to the vehicle transmitting the first of two detected low priority signals or the first of two detected high priority signals or the high priority signal of detected high and low priority signals.

Claims

1. A multiple priority remote control system responsive to at least two different optical energy signals transmitted from vehicles approaching a traffic intersection defined by at least two intersecting roadways for the remote control of a traffic control system for the intersection having a controller for controlling red, yellow and green traffic signal lights, the controller including a control switch for selectively connecting electrical power to the traffic lights with a timing control for timing the operation of the control switch, the remote control system including

a first detector means for the intersection for detecting the optical energy signals transmitted from vehicles approaching the intersection along one roadway for the intersection;

said first detector means having an output at which a signal is produced when an optical signal is detected;

a second detector means for the intersection for detecting the optical energy signals transmitted from vehicles approaching the intersection along another roadway for the intersection;

said second detector means having an output at which a signal is produced when an optical signal is detected;

a signal discriminator means operatively connected to said output of said first detector means for providing first and second control signals, said first control signal provided in response to detection by the first detector means of at least one of the optical energy signals, said second control signal provided in response to detection by the first detector means of a predetermined one of the possible optical energy signals;

said signal discriminator means operatively connected to said output of said second detector means for providing third and fourth control signals, said third control signal provided in response to detection by the second detector means of at least one of the optical energy signals, the fourth control signal provided in response to detection by the second detector means of the predetermined one of the possible optical energy signals;

a control circuit operatively connected to the controller, said signal discriminator means and the green light circuits of the traffic signal lights for each roadway of the intersection, said control circuit responsive to any one of said control signals for placing said control switch under the control of said control circuit to present the green light associated with such initial control signal except when said any one of said control signals is said first control signal and said fourth control signal is presented while said first control signal is present, said control circuit then responding, as though said fourth control signal was said any one of said control signals, to present the green light associated with said fourth control signal and except when said any one of said control signals is said third control signal and said second control signal is presented while said third control signal is present, said control circuit then responding, as though said second control signal was said any one of said control signals, to present the green light associated with said second control signal.

2. A multiple priority remote control system in accordance with claim 1 wherein said discriminator means includes a discriminator circuit, said discriminator circuit including a delay circuit portion and a coincidence circuit portion, each operatively connected to said output of said first detector means, said coincidence circuit portion connected for receiving the output of said delay circuit portion, said coincidence circuit portion providing a signal at its output each time coincidence occurs between a signal received at said coincidence circuit portion in response to a signal at said output of said first detector means and a signal from the output of said delay circuit portion;

and said discriminator circuit further including a circuit portion operatively connected to the output of said coincidence circuit for providing said second control signal upon receiving a predetermined number of signals from the output said coincidence circuit.

3. A priority remote control system in accordance with claim 2 wherein said discriminator circuit includes an input synchronizing circuit portion connected for providing said signal indicative of the detection of an optical signal by first detector means to said delay circuit portion and to said coincidence circuit portion, and a pulse generator circuit portion connected for timing the operation of said input synchronizing circuit portion, said delay circuit portion, said coincidence circuit portion and said circuit portion providing said second control signal.

4. A priority remote control system in accordance with claim 3 wherein said discriminator circuit includes a signal drop-out timer connected to said circuit portion providing said second control signal and to said pulse generator circuit portion for removing said second control signal a predetermined time after said first detector means is not detecting the optical energy signals which initiated said second control signal.

5. A priority remote control system in accordance with claim 2 wherein said discriminator circuit includes means operatively connected to said coincidence circuit and said delay circuit portion and responsive to one of said signals from the output of said coincidence circuit for preventing said coincidence circuit from providing another one of said signals at its output for a time period equal to the delay time of said delay circuit portion.