External adaptive control systems and methods

• US 8,253,592 B1
• Filed: 09/24/2008
• Issued: 08/28/2012
• Est. Priority Date: 11/26/2007
• Status: Active Grant

• Current Assignee: Rhythm Engineering
• Original Assignee: Rhythm Engineering
• Inventors: Chandra, Reggie J., Bley, James W., Penrod, Stephen S., Parker, Arthur S.
• Primary Examiner(s): Swarthout, Brent
• Application Number:
  US12/236,693
• Time in Patent Office: 1,434 Days
• Field of Search: 340907-924, 701/117, 701/118
• US Class Current: 340/917
• CPC Class Codes: G08G 1/07 Controlling traffic signals
• CPC Class Codes: G08G 1/081 Plural intersections under common control

Abstract

An external adaptive control system and method control a traffic signal controller assembly. The external adaptive control system determines a non-linear schedule with one or more states corresponding to one or more individual phases with each state having a start time and a duration. The external adaptive control system generates presence data for reception by the controller assembly for each state and its associated duration.

Claims

1. An external adaptive control system for controlling a traffic signal controller assembly for a plurality of individual phases at an intersection, comprising:

at least one interface to receive detector data for a plurality of individual phases;

a processing system comprising;

at least one processor;

a detector processing system operable on the at least one processor and configured to process the detector data to determine a queue length corresponding to each individual phase for which the detector data was received;

an optimizer system operable on the at least one processor and configured to determine a non-linear schedule based on the queue lengths for the individual phases, the non-linear schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration; and

a schedule system operable on the at least one processor and configured to sequentially generate presence data for each state in the non-linear schedule in the variable state order starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

a controller assembly interface configured to sequentially transmit the presence data corresponding to each state at each state start time and for each corresponding state duration for reception by the traffic signal controller assembly;

wherein the external adaptive control system is external to the traffic controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

2. The system of claim 1 wherein:

the at least one interface comprises at least one video camera interface;

at least some of the detector data comprises at least some video data; and

the external adaptive control system comprises a video processing system configured to operate on the at least one processor, to receive the at least some video data, and to process the at least some video data to determine at least one queue length for at least one individual phase.

3. The system of claim 1 wherein:

the at least one interface receives the detector data from a plurality of detectors; and

at least one of the detectors comprises at least one member of a group consisting of a loop detector, a video camera detector, and a puck (magnetic) detector.

4. The system of claim 1 further comprising:

at least one second interface to receive progression data for at least one progression, the progression data comprising at least one number of vehicles approaching the intersection and at least one progression time for the at least one number of vehicles approaching the intersection;

wherein the optimizer system is configured to process the progression data with the queue lengths for the individual phases to determine the non-linear schedule.

5. The system of claim 1 further comprising:

at least one second interface to receive progression data for a plurality of progressions approaching the intersection, the progression data comprising a number of vehicles approaching the intersection for each progression and a progression time for each number of vehicles approaching the intersection for each progression;

wherein the optimizer system is configured to process the progression data with the queue lengths for the individual phases to determine the non-linear schedule.

6. The system of claim 1 further comprising:

memory comprising at least one plan identifying at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement, a period for the at least one plan, a maximum green time for each of the plurality of individual phases, a minimum green time for each of the plurality of individual phases, a light change time for each of the plurality of individual phases, and permitted individual phases at the intersection;

wherein the optimizer system is configured to;

process inputs comprising the at least one plan, the period, the maximum green times for each of the plurality of individual phases, the minimum green times for each of the plurality of individual phases, the light change times for each of the plurality of individual phases, and the permitted individual phases at the intersection; and

determine the non-linear schedule based on the queue lengths for the individual phases and the inputs.

7. The system of claim 1 wherein the optimizer system is configured to determine at least one plan comprising at least one guaranteed green time and at least one minimum green duration for at least one selected direction of traffic movement and a period for the at least one plan and to determine the non-linear schedule based on the queue lengths for the individual phases and the at least one plan.

8. The system of claim 7 wherein the optimizer system is configured to determine the at least one plan by:

determining a number of vehicles per second passing through the intersection in the at least one direction of traffic movement during a prior period;

multiplying the number of vehicles per second by the prior period to determine an expected number of vehicles to pass through the intersection in the selected direction during the plan; and

multiplying a clearance time by the expected number of vehicles to determine the minimum green duration for the plan.

9. The system of claim 8 wherein the optimizer system further is configured to determine the at least one plan by determining the guaranteed green time to be a starting time of the plan.

10. The system of claim 7 wherein the optimizer system is configured to determine the at least one plan by:

determining a number of vehicles per second passing through the intersection in the at least one direction of traffic movement during a time frame the at least one direction of traffic movement has a right-of-way in a prior period;

multiplying the number of vehicles per second by the prior period to determine an expected number of vehicles to pass through the intersection in the selected direction during the plan; and

multiplying a clearance time by the expected number of vehicles to determine the minimum green duration for the plan.

11. The system of claim 7 wherein the optimizer system is configured to determine the period by:

reducing the period from a prior period by a first selected time amount when a non-selected direction of traffic movement at the intersection has more than enough time during the prior period to clear traffic for at least one corresponding individual phase in the non-selected direction; and

increasing the period from the prior period by a second selected time amount when the non-selected direction of traffic movement at the intersection does not have enough time during the prior period to clear the traffic for the at least one corresponding individual phase in the non-selected direction.

12. The system of claim 7 wherein the optimizer system is configured to determine the period by:

reducing the period from a prior period by a first selected time amount when the selected direction of traffic movement at the intersection has more than enough time during the prior period to clear traffic for at least one corresponding individual phase in the selected direction; and

increasing the period from the prior period by a second selected time amount when the selected direction of traffic movement at the intersection does not have enough time during the prior period to clear the traffic for the at least one corresponding individual phase in the selected direction.

13. The system of claim 7 wherein the processing system is configured to determine the intersection is a critical intersection and the system comprises a network interface configured to transmit the at least one plan from the external adaptive control system.

14. The system of claim 13 wherein the detector processing system is configured to process traffic count data to determine a current traffic count passing through the intersection for at least one individual phase at the intersection, the processing system is configured to generate the traffic count for the at least one individual phase, and the network interface is configured to transmit the traffic count for the at least one individual phase from the external adaptive control system.

15. The system of claim 13 wherein:

the detector data comprises video data;

the detector processing system comprises a video processing system configured to process the video data to determine a current traffic count passing through the intersection for at least one individual phase; and

the network interface is configured to transmit the current traffic count for the at least one individual phase from the external adaptive control system.

16. The system of claim 13 further comprising another external adaptive control system configured to receive the at least one plan.

17. The system of claim 1 wherein the presence data for each state corresponds to detector calls for up to two individual phases.

18. The system of claim 1 wherein the presence data for each state corresponds to (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases.

19. The system of claim 1 wherein the presence data corresponding to each state comprises a communication comprising data corresponding to (i) a presence of at least one vehicle in each of up to two individual phases for each state, even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases for each state, even if vehicles are actually present in one or more of said up to two individual phases.

20. The system of claim 1 wherein:

the processing system comprises a detector manager configured to determine when at least some detector data is not received;

the external adaptive control system comprises historical data comprising prior light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame; and

the optimizer system is configured to process the historical data in place of the not received detector data to determine the non-linear schedule.

21. The system of claim 1 wherein:

the controller assembly interface is configured to receive from the traffic signal controller assembly a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

the external adaptive control system comprises memory to store the plurality of light states as historical data;

the processing system comprises an emergency mode operational when at least some of the detector data is not received at the controller assembly interface; and

the optimizer system is configured to process at least some of the historical data in place of at least some of the queue length data in the emergency mode to determine the non-linear schedule.

22. The system of claim 1 wherein the optimizer system is configured to determine the non-linear schedule by determining first states, first state start times, and first state durations for a main direction, determining second states, second state start times, and second state durations for a cross street direction, and ordering the first states and second states in any desirable variable order.

23. The system of claim 1 determine the non-linear schedule by:

establishing a start time for the non-linear schedule and an end time for the non-linear schedule;

determining a first partial schedule by marking time occupied by coordinated phases as committed;

for each individual phase with an unaccounted queue, determine a plurality of potential schedules from the first partial schedule by fitting the unaccounted individual phase into areas where no non-compatible phase already exists;

applying a scoring function to each potential schedule, the scoring function comprising multiplying each queue length for each unaccounted individual phase by a waiting time for the unaccounted individual phase and summing each multiplied queue length and waiting time to obtain a score for each potential schedule;

selecting the potential schedule with a lowest score as the non-linear schedule;

filling at least one empty area in the schedule with at least one compatible individual phase; and

generating the non-linear schedule from the potential schedule with the lowest score and the at least one compatible individual phase.

24. The system of claim 1 wherein the optimizer system is configured to determine a plurality of potential solutions for a main direction and a cross street direction based on the queue lengths, each potential solution having transition times and waiting times for a plurality of potential state sequences, to select a solution for each direction having a lowest waiting time and a shortest transition time, and to generate the non-linear schedule with the selected main street solution and the selected cross street solution.

25. The system of claim 1 wherein the controller assembly interface is configured to generate the presence data for each state in at least one communication and the system further comprises:

an input output card configured in the traffic signal controller assembly to receive each communication; and

a detector card to format each communication into a form processable by a controller unit in the traffic signal controller assembly.

26. An external adaptive control system for controlling a traffic signal controller assembly to control traffic movement for a plurality of individual phases at an intersection, comprising:

at least one interface to receive detector data for a plurality of individual phases;

a processing system comprising;

at least one processor;

a detector processing system operable on the at least one processor and configured to process the detector data to determine a queue length corresponding to each individual phase for which the detector data was received;

an optimizer system operable on the at least one processor and configured to;

determine at least one plan identifying at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement and a period for the at least one plan; and

determine a non-linear schedule based on the queue lengths for the individual phases and the at least one plan, the non-linear schedule comprising a period and any desirable variable order of a plurality of states, each state having a state start time and a state duration;

a schedule system operable on the at least one processor and configured to sequentially generate presence data for each state in the non-linear schedule in the variable order starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

a controller assembly interface configured to sequentially transmit the presence data corresponding to each state at each state start time and for each state duration for reception by the controller assembly;

wherein the external adaptive control system is external to the traffic controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

27. The system of claim 26 wherein the presence data for each state corresponds to at least one member of a group consisting of detector calls for up to two individual phases and (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases.

28. The system of claim 26 wherein:

the controller assembly interface is configured to receive from the traffic signal controller assembly a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

the external adaptive control system comprises memory to store the plurality of light states as historical data;

the processing system comprises an emergency mode operational when at least some of the detector data is not received at the controller assembly interface; and

the optimizer system is configured to process at least some of the historical data in place of at least some of the queue length data in the emergency mode to determine the non-linear schedule.

29. The system of claim 26 wherein the optimizer system is configured to determine the non-linear schedule by determining first states, first state start times, and first state durations for a main direction, determining second states, second state start times, and second state durations for a cross street direction, and ordering the first states and second states in the variable order.

30. The system of claim 26 wherein the optimizer system is configured to determine a plurality of potential solutions based on the queue lengths, each potential solution having waiting times for a plurality of potential state sequences, to select a solution having a lowest waiting time, and to generate the non-linear schedule with the selected solution.

31. An external adaptive control system for controlling a traffic signal controller assembly at an intersection having a plurality of individual traffic movements, comprising:

at least one interface to receive detector data for at least some of the plurality of traffic movements;

a processing system comprising;

at least one processor;

a detector processing system operable on the at least one processor and configured to process the detector data to determine a queue length corresponding to each individual phase for which the detector data was received;

an optimizer system operable on the at least one processor and configured to determine a non-linear schedule based on the queue lengths for the traffic movements, the non-linear schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration;

a schedule system operable on the at least one processor and configured to sequentially generate presence data for each state in the schedule starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

a controller assembly interface configured to sequentially transmit the presence data corresponding to each state at each state start time and for each state duration for reception by the controller assembly;

wherein the external adaptive control system is external to the traffic controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

32. The system of claim 31 wherein the optimizer system is configured to determine at least one plan comprising at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement and a period for the at least one plan and to determine the non-linear schedule based on the queue lengths for the individual phases, the at least one plan, and the period for the at least one plan.

33. The system of claim 31 wherein:

the controller assembly interface is configured to receive from the traffic signal controller assembly a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

the external adaptive control system comprises memory to store the plurality of light states as historical data;

the processing system comprises an emergency mode operational when at least some of the detector data is not received at the controller assembly interface; and

the optimizer system is configured to process at least some of the historical data in place of at least some of the queue length data in the emergency mode to determine the non-linear schedule.

34. The system of claim 31 wherein the optimizer system is configured to determine the non-linear schedule by determining first states, first state start times, and first state durations for a main direction, determining second states, second state start times, and second state durations for a cross street direction, and ordering the first states and second states in the variable order.

35. The system of claim 31 wherein the optimizer system is configured to determine a plurality of potential solutions based on the queue lengths, each potential solution having waiting times for a plurality of potential state sequences, to select a solution having a lowest waiting time, and to generate the non-linear schedule with the selected solution.

36. An external adaptive control system for controlling a traffic signal controller assembly for a plurality of individual phases at an intersection, comprising:

at least one interface to receive detector data for a plurality of individual phases;

a processing system comprising;

at least one processor;

a detector processing system operable on the at least one processor and configured to process the detector data to determine a queue length corresponding to each individual phase for which the detector data was received;

an optimizer system operable on the at least one processor and configured to;

determine a plan comprising at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement at the intersection and a period for the plan; and

determine a non-linear schedule based on the plan and the queue lengths for the individual phases, the non-linear schedule comprising any desirable variable order of a plurality of states having a variable order, each state having a state start time and a state duration; and

a schedule system operable on the at least one processor and configured to sequentially generate presence data for each state in the non-linear schedule in the variable order starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

a controller assembly interface configured to sequentially transmit the presence data corresponding to each state at each state start time and for each corresponding state duration for reception by the traffic signal controller assembly;

wherein the external adaptive control system is external to the traffic controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

37. The system of claim 36 wherein:

the processing system comprises a detector manager configured to determine when at least some detector data is not received;

the external adaptive control system comprises historical data comprising prior light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame; and

the optimizer system is configured to process the historical data in place of the not received detector data to determine the non-linear schedule.

38. The system of claim 36 wherein:

the controller assembly interface is configured to receive from the traffic signal controller assembly a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

the external adaptive control system comprises memory to store the plurality of light states as historical data;

the processing system comprises an emergency mode operational when at least some of the detector data is not received at the controller assembly interface; and

the optimizer system is configured to process at least some of the historical data in place of at least some of the queue length data in the emergency mode to determine the non-linear schedule.

39. An external adaptive control system for controlling a traffic signal controller assembly in a fully actuated mode for a plurality of individual phases at an intersection, comprising:

at least one interface to receive detector data for a plurality of individual phases;

a processing system comprising;

at least one processor;

a detector processing system operable on the at least one processor and configured to process the detector data to determine a queue length corresponding to each individual phase for which the detector data was received;

an optimizer system operable on the at least one processor and configured to;

determine a plan comprising at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement at the intersection and a period for the plan; and

determine a non-linear schedule based on the plan and the queue lengths for the individual phases, the non-linear schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration; and

a schedule system operable on the at least one processor and configured to sequentially generate presence data for each state in the non-linear schedule in the variable order starting at each state start time and for each state duration, the presence data corresponding to (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases; and

a controller assembly interface configured to sequentially transmit the presence data corresponding to each state at each state start time and for each corresponding state duration for reception by the traffic signal controller assembly;

wherein the external adaptive control system is external to the traffic controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

40. A method for controlling a traffic signal controller assembly at an intersection, the method comprising:

receiving detector data for a plurality of individual phases for the intersection at at least one interface of an external adaptive control system that is external to the traffic signal controller assembly, the external adaptive control system comprising a controller assembly interface, a processing system comprising a processor, a detector processing system operable on the at least one processor, an optimizer system operable on the at least one processor, and a schedule system operable on the at least one processor;

processing the detector data at the detector processing system to determine a queue length corresponding to each individual phase for which the detector data was received;

determining a non-linear schedule at the optimizer system based on the queue lengths for the individual phases, the non-linear schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration;

sequentially generating presence data at the schedule system for each state in the non-linear schedule in the variable state order starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

sequentially transmitting the presence data corresponding to each state at each state start time and for each corresponding state duration from the controller assembly interface for reception by the traffic signal controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

41. The method of claim 40 further comprising:

receiving the detector data from a plurality of detectors, wherein at least one of the detectors comprises at least one member of a group consisting of a loop detector, a video camera detector, and a puck (magnetic) detector.

42. The method of claim 40 further comprising:

receiving progression data for a plurality of progressions approaching the intersection at at least one second interface, the progression data comprising a number of vehicles approaching the intersection for each progression and a progression time for each number of vehicles approaching the intersection for each progression; and

processing the progression data with the queue lengths for the individual phases at the optimizer system to determine the non-linear schedule.

43. The method of claim 40 further comprising:

determining at least one plan at the optimizer system, the plan comprising at least one guaranteed green time and at least one minimum green duration for at least one selected direction of traffic movement and a period for the at least one plan; and

determining the non-linear schedule based on the queue lengths for the individual phases and the at least one plan.

44. The method of claim 43 further comprising determining the at least one plan by:

determining a number of vehicles per second passing through the intersection in the at least one direction of traffic movement during a prior period;

multiplying the number of vehicles per second by the prior period to determine an expected number of vehicles to pass through the intersection in the selected direction during the plan; and

multiplying a clearance time by the expected number of vehicles to determine the minimum green duration for the plan.

45. The method of claim 43 further comprising determining the at least one plan by determining the guaranteed green time to be a starting time of the plan.

46. The method of claim 43 further comprising determining the at least one plan by:

determining a number of vehicles per second passing through the intersection in the at least one direction of traffic movement during a time frame the at least one direction of traffic movement has a right-of-way in a prior period;

multiplying the number of vehicles per second by the prior period to determine an expected number of vehicles to pass through the intersection in the selected direction during the plan; and

multiplying a clearance time by the expected number of vehicles to determine the minimum green duration for the plan.

47. The method of claim 43 further comprising determining the period by:

reducing the period from a prior period by a first selected time amount when a non-selected direction of traffic movement at the intersection has more than enough time during the prior period to clear traffic for at least one corresponding individual phase in the non-selected direction; and

increasing the period from the prior period by a second selected time amount when the non-selected direction of traffic movement at the intersection does not have enough time during the prior period to clear the traffic for the at least one corresponding individual phase in the non-selected direction.

48. The method of claim 43 further comprising determining the period by:

reducing the period from a prior period by a first selected time amount when the selected direction of traffic movement at the intersection has more than enough time during the prior period to clear traffic for at least one corresponding individual phase in the selected direction; and

increasing the period from the prior period by a second selected time amount when the selected direction of traffic movement at the intersection does not have enough time during the prior period to clear the traffic for the at least one corresponding individual phase in the selected direction.

49. The method of claim 43 further comprising:

determining the intersection is a critical intersection;

transmitting the at least one plan from a network interface of the external adaptive control system; and

receiving the at least one plan at another external adaptive control system.

50. The method of claim 40 wherein transmitting the presence data corresponding to each state comprises transmitting at least one member of a group consisting of detector calls for up to two individual phases and (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases.

51. The method of claim 40 wherein transmitting the presence data corresponding to each state comprises transmitting a communication comprising data corresponding to (i) a presence of at least one vehicle in each of up to two individual phases for each state, even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases for each state, even if vehicles are actually present in one or more of said up to two individual phases.

52. The method of claim 40 wherein the external adaptive control system comprises a detector manager and historical data comprising prior light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame and the method further comprises:

determining when at least some detector data is not received at the detector manager; and

processing the historical data in place of the not received detector data at the optimizer system to determine the non-linear schedule.

53. The method of claim 40 further comprising:

receiving, from the traffic signal controller assembly at the controller assembly interface, a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

storing the plurality of light states as historical data in memory of the external adaptive control system; and

processing at least some of the historical data in place of at least some of the queue length data in an emergency mode of the optimizer system to determine the non-linear schedule when at least some of the detector data is not received at the controller assembly interface.

54. The method of claim 40 further comprising determining the non-linear schedule by determining first states, first state start times, and first state durations for a main direction, determining second states, second state start times, and second state durations for a cross street direction, and ordering the first states and second states in the variable state order.

55. The method of claim 40 further comprising determining the non-linear schedule by:

establishing a start time for the non-linear schedule and an end time for the non-linear schedule;

determining a first partial schedule by marking time occupied by coordinated phases as committed;

for each individual phase with an unaccounted queue, determine a plurality of potential schedules from the first partial schedule by fitting the unaccounted individual phase into areas where no non-compatible phase already exists;

applying a scoring function to each potential schedule, the scoring function comprising multiplying each queue length for each unaccounted individual phase by a waiting time for the unaccounted individual phase and summing each multiplied queue length and waiting time to obtain a score for each potential schedule;

selecting the potential schedule with a lowest score as the non-linear schedule;

filling at least one empty area in the schedule with at least one compatible individual phase; and

generating the non-linear schedule from the potential schedule with the lowest score and the at least one compatible individual phase.

56. A method for controlling a traffic signal controller assembly at an intersection, the method comprising:

receiving detector data for a plurality of individual phases for the intersection at at least one interface of an external adaptive control system that is external to the traffic signal controller assembly, the external adaptive control system comprising a controller assembly interface, a processing system comprising a processor, a detector processing system operable on the at least one processor, an optimizer system operable on the at least one processor, and a schedule system operable on the at least one processor;

processing the detector data at the detector processing system to determine a queue length corresponding to each individual phase for which the detector data was received;

determining at least one plan at the optimizer system, the at least one plan identifying at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement and a period for the at least one plan;

determining a non-linear schedule at the optimizer system based on the queue lengths for the individual phases and the at least one plan, the non-linear schedule comprising a period and any desirable variable order of a plurality of states, each state having a state start time and a state duration;

sequentially generating at the schedule system presence data for each state in the non-linear schedule in the variable order starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

sequentially transmitting the presence data corresponding to each state at each state start time and for each state duration from the controller assembly interface for reception by the controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

57. The method of claim 56 wherein transmitting the presence data corresponding to each state comprises transmitting at least one member of a group consisting of detector calls for up to two individual phases and (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases.

58. The method of claim 56 further comprising:

receiving, from the traffic signal controller assembly at the controller assembly interface, a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

storing the plurality of light states as historical data in memory of the external adaptive control system; and

processing at least some of the historical data in place of at least some of the queue length data in an emergency mode of the optimizer system to determine the non-linear schedule when at least some of the detector data is not received at the controller assembly interface.

59. The method of claim 56 further comprising determining the non-linear schedule by determining first states, first state start times, and first state durations for a main direction, determining second states, second state start times, and second state durations for a cross street direction, and ordering the first states and second states in the variable order.

60. The method of claim 56 further comprising:

determining a plurality of potential solutions for a main direction and a cross street direction based on the queue lengths, each potential solution having transition times and waiting times for a plurality of potential state sequences;

selecting a solution for each direction having a lowest waiting time and a shortest transition time; and

generating the non-linear schedule with the selected main street solution and the selected cross street solution.

61. A method for controlling a traffic signal controller assembly at an intersection, the method comprising:

receiving detector data for a plurality of individual phases for the intersection at an external adaptive control system that is external to the traffic signal controller assembly;

processing the detector data with a processor at the external adaptive control system to determine a queue length corresponding to each individual phase for which the detector data was received;

determining a non-linear schedule at the external adaptive control system based on the queue lengths for the traffic movements, the schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration;

sequentially generating presence data for each state in the schedule starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

sequentially transmitting the presence data corresponding to each state at each state start time and for each state duration from the external adaptive control system for reception by the controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

62. The method of claim 61 further comprising:

determining at the external adaptive control system a plan comprising at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement and a period for the at least one plan; and

determining the non-linear schedule based on the queue lengths for the individual phases, the at least one plan, and the period for the at least one plan.

63. The method of claim 61 wherein:

receiving, from the traffic signal controller assembly at the external adaptive control system, a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

storing the plurality of light states as historical data in memory of the external adaptive control system; and

processing at least some of the historical data in place of at least some of the queue length data in an emergency mode of the external adaptive control system to determine the non-linear schedule when at least some of the detector data is not received at the controller assembly interface.

64. The method of claim 61 further comprising:

determining a plurality of potential solutions based on the queue lengths, each potential solution having waiting times for a plurality of potential state sequences;

selecting a solution for having a lowest waiting time; and

generating the non-linear schedule with the selected solution.

65. A method for controlling a traffic signal controller assembly at an intersection, the method comprising:

receiving detector data for a plurality of individual phases for the intersection at at least one interface of an external adaptive control system that is external to the traffic signal controller assembly, the external adaptive control system comprising a controller assembly interface, a processing system comprising a processor, a detector processing system operable on the at least one processor, an optimizer system operable on the at least one processor, and a schedule system operable on the at least one processor;

processing the detector data at the detector processing system to determine a queue length corresponding to each individual phase for which the detector data was received;

determining a plan at the optimizer system, the plan comprising at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement at the intersection and a period for the plan; and

determining a non-linear schedule at the optimizer system based on the plan and the queue lengths for the individual phases, the non-linear schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration; and

sequentially generating presence data from the schedule system for each state in the nonlinear schedule in the variable order starting at each state start time and for each state duration, the presence data corresponding to (i) an absence of vehicles at an approach to the intersection even if vehicles are actually present at said approach, or (ii) a presence of vehicles at the approach to the intersection even if no vehicles are actually present at said approach; and

sequentially transmitting the presence data corresponding to each state at each state start time and for each corresponding state duration from the controller assembly interface for reception by the traffic signal controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.

66. The method of claim 65 wherein transmitting the presence data corresponding to each state comprises transmitting a communication for each state comprising data corresponding to (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicles are actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases.

67. The method of claim 65 wherein the external adaptive control system comprises a detector manager and historical data comprising prior light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame and the method further comprises:

determining when at least some detector data is not received at the detector manager; and

processing the historical data in place of the not received detector data at the optimizer system to determine the non-linear schedule.

68. The method of claim 65 further comprising:

receiving, from the traffic signal controller assembly at the controller assembly interface, a plurality of light states generated by the traffic signal controller assembly for particular individual phases for a configured time frame;

storing the plurality of light states as historical data in memory of the external adaptive control system; and

processing at least some of the historical data in place of at least some of the queue length data in an emergency mode of the optimizer system to determine the non-linear schedule when at least some of the detector data is not received at the controller assembly interface.

69. A method for controlling a traffic signal controller assembly at an intersection, the method comprising:

receiving detector data for a plurality of individual phases for the intersection at at least one interface of an external adaptive control system that is external to the traffic signal controller assembly, the external adaptive control system comprising a controller assembly interface, a processing system comprising a processor, a detector processing system operable on the at least one processor, an optimizer system operable on the at least one processor, and a schedule system operable on the at least one processor;

processing the detector data at the detector processing system to determine a queue length corresponding to each individual phase for which the detector data was received;

determining a plan at the optimizer system, the plan comprising at least one guaranteed green time and at least one minimum green duration for at least one direction of traffic movement at the intersection and a period for the plan;

determine a non-linear schedule at the optimizer system based on the plan and the queue lengths for the individual phases, the non-linear schedule comprising any desirable variable order of a plurality of states, each state having a state start time and a state duration; and

sequentially generating presence data at the schedule system for each state in the non-linear schedule in the variable order starting at each state start time and for each state duration, the presence data corresponding to (i) a presence of at least one vehicle in each of up to two individual phases even if no vehicle is actually present in one or more of said up to two individual phases, or (ii) an absence of vehicles in said up to two individual phases even if vehicles are actually present in one or more of said up to two individual phases; and

sequentially transmitting the presence data corresponding to each state at each state start time and for each corresponding state duration from the controller assembly interface for reception by the traffic signal controller assembly;

whereby the external adaptive control system causes the traffic signal controller assembly to operate according to the non-linear schedule instead of a predefined linear schedule.