TRAFFIC CONTROL SYSTEM

• US 3,613,073 A
• Filed: 05/14/1969
• Issued: 10/12/1971
• Est. Priority Date: 05/14/1969
• Status: Expired due to Term

• Current Assignee: Eugene Emerson Clift
• Original Assignee: Eugene Emerson Clift
• Inventors: Clift, Eugene Emerson
• Primary Examiner(s): Cooper, William C.
• Application Number:
  US04/824,520
• Time in Patent Office: 881 Days
• Field of Search: 340/31,31A,35
• US Class Current: 340/920
• CPC Class Codes: G08G 1/08 according to detected number or speed of vehicles

Abstract

A traffic control system for regulating the movement of traffic at an intersection, including magnetic sensors at the entrance and exit ends of each lane leaving said intersection for producing vehicle count signals for each vehicle entering and leaving the lane, and traffic lights at said intersection having controllers for varying the cycles, offsets and splits thereof for regulating flow of traffic across the intersection into each of said lanes. Counters respond to the count signals for determining the number of vehicles in each selected street block and logic means respond to the counters for determining the direction of the greatest traffic flow and applying control signals to said traffic signal light controllers to control the same in response to the sensed traffic conditions.

Claims

1. In a traffic control system for regulating the movement of traffic into the leaving lanes of four street sections of selected length leaving in four directions from a roadway intersection, each leaving lane having an entrance end at said intersection and an exit end at the end of said selected length of the street section, a first vehicle detector at the entrance end of each lane leaving said intersection for producing a counter advance signal for each vehicle entering the associated lane, a second vehicle detector at the exit end of each of said lanes for generating a counter subtract signal for each of the vehicles leaving the associated street section for each of said lanes, traffic signal lights at said intersection including traffic light controller means for operating the signal lights in a plurality of different time duration cycles to regulate flow of traffic across said intersection into each of said lanes, plural counting means including a counter for each respective street section for continuously counting the vehicles collectively in all of the leaving lanes of the associated street section responsive to the advance and subtract signals from the detectors for the leaving lanes of the associated street section, each counter having an array or contacts controlled in accordance with the counts for establishing combinations of open and closed contact conditions indicating the collective count of the number of vehicles in the leaving lanes of the associated street section, and logic means responsive to said contact conditions for determining the direction of the greatest traffic flow and applying control signals to said traffic light controller means to control the cycles of said traffic signal lights in selected relation to the sensed traffic conditions.

2. A traffic control system as defined in claim 1, wherein said logic means includes saturation control means coupled to said counting means and responsive to selected contact conditions thereof to determine existence of a vehicle saturation level in any of said street sections and activate said traffic signal lights to halt traffic flow into the lanes of the saturated street section as long as the saturation level persists.

3. A traffic control system as defined in claim 2, wherein said logic means includes route control means to select the next highest count below the saturation level signified by the contact conditions of said counters and control the traffic signal lights in selected relation to said next highest count to permit a continued flow of traffic to unsaturated street sections.

4. A traffic control system as defined in claim 1, wherein said logic means includes means to halt traffic flow into the lanes of a street section having a vehicle saturation level and means for controlling the traffic signal light to maintain traffic flow into the nonsaturated street sections.

5. A traffic control system as defined in claim 1, wherein said counter for each respective street section includes a counter circuit and said array of contacts controlled thereby is arranged in a numerical series and regulated thereby to produce closure of contacts whose position signifies the number of vehicles in the associated street section, said contacts of such array being grouped in a plurality of serially arranged sets of plural contacts each signifying progressively increasing traffic density levels, and said logic means including a relay coupled to each respective set of contacts to be activated when contacts of its associated set are closed, and the relays associated with said array are coupled to said controller means to respectively establish progressively longer duration traffic signal light cycles for contact closures signifying progressively higher numbers of vehicles.

6. A traffic control system as defined in claim 2, wherein said counter for each respective street section includes a counter circuit and said array of contacts controlled thereby is arranged in a numerical series and regulated thereby to produce closure of contacts whose position signifies the number of vehicles in the associated street section, said contacts of such array being grouped in a plurality of serially arranged sets of plural contacts each signifying progressively increasing traffic density levels, and said logic means including a relay coupled to each respective set of contacts to be activated when contacts of its associated set are closed, and the relays associated with said array are coupled to said controller means to respectively establish progressively longer duration traffic signal light cycles for contact closures signifying progressively higher numbers of vehicles.

7. A traffic control system as defined in claim 3, wherein said counter for each respective street section includes a counter circuit and said array of contacts controlled thereby is arranged in a numerical series and regulated thereby to produce closure of contacts whose position signifies the number of vehicles in the associated street section, said contacts of such array being grouped in a plurality of serially arranged sets of plural contacts each signifying progressively increasing traffic density levels, and said logic means including a relay coupled to each respective set of contacts to be activated when contacts of its associated set are closed, and the relays associated with said array are coupled to said controller means to respectively establish progressively longer duration traffic signal light cycles for contact closures signifying progressively higher numbers of vehicles.

8. A traffic control system as defined in claim 4, wherein said counter for each respective street section includes a counter circuit and said array of contacts controlled thereby is arranged in a numerical series and regulated thereby to produce closure of contacts whose position signifies the number of vehicles in the associated street section, said contacts of such array being grouped in a plurality of serially arranged sets of plural contacts each signifying progressively increasing traffic density levels, and said logic means including a relay coupled to each respective set of contacts to be activated when contacts of its associated set are closed, and the relays associated with said array are coupled to said controller means to respectively establish progressively longer duration traffic signal light cycles for contact closures signifying progressively higher numbers of vehicles.

9. A traffic control system as defined in claim 1, wherein said logic means includes means responsive to different count levels of said counting means to provide different offset and split control signals for application to said controller means which vary in selected relation to the count levels.

10. A traffic control system as defined in claim 2, wherein said logic means includes means responsive to different count levels of said counting means to provide different offset and split control signals for application to said controller means which vary in selected relation to the count levels.

11. A traffic control system as defined in claim 3, wherein said logic means includes means responsive to different count levels of said counting means to provide different offset and split control signals for application to said controller means which vary in selected relation to the count levels.

12. A traffic control system as defined in claim 5, wherein said logic means includes means responsive to different count levels of said counting means to provide different offset and split control signals for application to said controller means which vary in selected relation to the count level.

13. A traffic control system as defined in claim 5, wherein each of said relays associated with each said array includes relay contact means for establishing offset and split control signals for said controller means which differ for respective sets of said contacts.

14. A traffic control system as defined in claim 6, wherein each of said relays associated with each said array includes relay contact means for establishing offset and split control signals for said controller means which differ for respective sets of said contacts.

15. A traffic control system as defined in claim 7, wherein each of said relays associated with each said array includes relay contact means for establishing offset and split control signals for said controller means which differ for respective sets of said contacts.

16. A traffic control system as defined in claim 1, including timing means to reset said counting means at least once every 24 hours.

17. A traffic control system as defined in claim 1, including relay means activated responsive to selected failure conditions in said logic means to produce signals for activating the associated traffic signal light in a flashiNg yellow condition.

18. A traffic control system as defined in claim 1, wherein said logic means includes means for providing control signals for a plurality of different cycles, offsets and splits to apply control signals to said controller means establishing multiple cycles, offsets and splits which differ in selected relation to the count levels of said counting means.

19. A traffic control system as defined in claim 2, wherein said logic means includes means for providing control signals for a plurality of different cycles, offsets and splits to apply control signals to said controller means establishing multiple cycles, offsets and splits which differ in selected relation to the count levels of said counting means.

20. A traffic control system as defined in claim 13 wherein said relay contact means for establishing offset and split control signals are associated with said relays in such relation to provide multiple offsets and splits having multiple settings which vary in preselected relation to the traffic density levels signified by said sets of contacts.

21. A traffic control system as defined in claim 14 wherein said relay contact means for establishing offset and split control signals are associated with said relays in such relation to provide multiple offsets and splits having multiple settings which vary in preselected relation to the traffic density levels signified by said sets of contacts.