TRAFFIC SIGNAL CONTROL METHOD AND TRAFFIC SIGNAL CONTROLLER

• US 20140375475A1
• Filed: 01/10/2013
• Published: 12/25/2014
• Est. Priority Date: 01/10/2012
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology, Nanyang Technological University
• Original Assignee: Massachusetts Institute of Technology, Nanyang Technological University
• Inventors: Frazzoli, Emilio, Wang, Yu, Wongpiromsarn, Tichakorn, Wang, Danwei, Uthaicharoenpong, Tawit
• Granted Patent: US 9,601,013 B2
• Time in Patent Office: Days
• US Class Current: 340/907
• CPC Class Codes: G08G 1/01 Detecting movement of traffic to be counted or controlled G08G1/07 - G08G1/14 take precedence
• CPC Class Codes: G08G 1/08 according to detected number or speed of vehicles
• CPC Class Codes: G08G 1/083 Controlling the allocation of time between phases of a cycle

Abstract

A distributed traffic signal control method is provided for a directed network comprising a plurality of junctions, each junction having a plurality of links connected thereto, the links comprising one or more upstream links and one or more downstream links, the method comprising: activating one of a plurality of phases of the junction for a predetermined time period which maximizes the directed network throughput based on current differential traffic backlogs between said one or more upstream links and said one or more downstream links, each phase providing a unique combination of traffic signals at the junction for guiding traffic from the upstream link(s) to the downstream link(s). There is also provided a corresponding traffic signal controller, a traffic control system comprising the traffic signal controller, and a computer readable medium having stored therein computer executable codes for instructing a computer processor to execute the distributed traffic signal control method.

Claims

1. A distributed traffic signal control method for a directed network comprising a plurality of junctions, each junction having a plurality of links connected thereto, the links comprising one or more upstream links and one or more downstream links, the method comprising:

activating one of a plurality of phases of the junction for a predetermined time period which maximizes the directed network throughput based on current differential traffic backlogs between said one or more upstream links and said one or more downstream links connected to the junction, each phase providing a unique combination of traffic signals at the junction for guiding traffic from said one or more upstream links to said one or more downstream links.

2. The method according to claim 1, wherein each current differential traffic backlog is determined based on a difference between a current traffic condition of one of the downstream links and a current traffic condition of one of the upstream links.

3. The method according to claim 2, wherein the current traffic condition comprises a queue length of vehicles at the link.

4. The method according to claim 1, wherein said activating one of a plurality of phases is based on said current differential traffic backlogs and a flow rate of traffic through the junction.

5. The method according to claim 4, wherein the flow rate of traffic through the junction is determined based on a comparison of a current traffic state at the junction with a prior model or data so as to locate a predetermined flow rate corresponding to the current traffic state.

6. The method according to claim 4, wherein the flow rate is measured by a traffic monitoring system at the junction.

7. The method according to claim 4, further comprises, determining, for each phase, a parameter based on a sum of the multiplication of the current differential traffic backlog with the flow rate of traffic for each unique combination of one upstream link and one downstream link of the plurality of links connected to the junction.

8. The method according to claim 7, further comprises determining one or more phases having the parameter with a largest value, wherein said activating one of a plurality of phases comprises selecting one of said one or more phases having the parameter with the largest value.

9. The method according to claim 1, wherein the upstream link is a link for providing inflow of traffic to the junction and the downstream link is a link for receiving outflow of traffic from the junction.

10. A traffic signal controller for a directed network comprising a plurality of junctions, each junction having a plurality of links connected thereto, the links comprising one or more upstream links and one or more downstream links, the controller comprising:

a control unit for activating one of a plurality of phases of the junction for a predetermined time period which maximizes the directed network throughput based on current differential traffic backlogs between said one or more upstream links and said one or more downstream links connected to the junction, each phase providing a set of traffic signals at the junction for guiding traffic from said one or more upstream links to said one or more downstream links.

11. The controller according to claim 10, wherein each current differential traffic backlog is determined based on a difference between a current traffic condition of one of the downstream links and a current traffic condition of one of the upstream links.

12. The controller according to claim 11, wherein the current traffic condition comprises a queue length of vehicles at the link.

13. The controller according to claim 10, wherein the control unit is operable to activate said one of a plurality of phases based on said current differential traffic backlogs and a flow rate of traffic through the junction.

14. The controller according to claim 13, wherein the flow rate of traffic through the junction is determined based on a comparison of a current traffic state at the junction with a prior model or data so as to locate a predetermined flow rate corresponding to the current traffic state.

15. The controller according to claim 13, wherein the flow rate is measured by a traffic monitoring system at the junction.

16. The controller according to claim 13, wherein for each phase, the control unit is operable to determine a parameter based on a sum of the multiplication of the current differential traffic backlog with the flow rate of traffic for each unique combination of one upstream link and one downstream link of the plurality of links connected to the junction.

17. The controller according to claim 16, wherein the controller is further operable to determine one or more phases having the parameter with a largest value, wherein said one of a plurality of phases activated is one of said one or more phases having the parameter with the largest value.

18. The controller according to claim 10, wherein the upstream link is a link for providing inflow of traffic to the junction and the downstream link is a link for receiving outflow of traffic from the junction.

19. A traffic control system for a directed network comprising a plurality of junctions, each junction having a plurality of links connected thereto, the links comprising one or more upstream links and one or more downstream links, the system comprising:

one or more traffic signal controllers for directing traffic through one or more junctions in the directed network; and

one or more traffic monitoring units for monitoring current traffic condition at one or more links and providing data indicative of the current traffic condition at said one or more links to the traffic signal controllers,

wherein the traffic signal controller for directing traffic comprises a control unit for activating one of a plurality of phases of the junction for a predetermined time period which maximizes the directed network throughput based on current differential traffic backlogs between said one or more upstream links and said one or more downstream links connected to the junction, each phase providing a set of traffic signals at the junction for guiding traffic from said one or more upstream links to said one or more downstream links.

20. A non-transitory computer readable medium having stored therein computer executable codes for instructing a computer processor to execute a distributed traffic signal control method, for a directed network comprising a plurality of junctions, each junction having a plurality of links connected thereto, the links comprising one or more upstream links and one or more downstream links, the method comprising:

activating one of a plurality of phases of the junction for a predetermined time period which maximizes the directed network throughput based on current differential traffic backlogs between said one or more upstream links and said one or more downstream links connected to the junction, each phase providing a unique combination of traffic signals at the junction for guiding traffic from said one or more upstream links to said one or more downstream links.