Monitoring signalized traffic flow

• US 7,991,542 B2
• Filed: 03/21/2007
• Issued: 08/02/2011
• Est. Priority Date: 03/24/2006
• Status: Active Grant

• Current Assignee: Wavetronix
• Original Assignee: Wavetronix
• Inventors: Miller, Michael J., Giles, Bradley C.
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US11/689,441
• Publication Number:
  US 20070222639A1
• Time in Patent Office: 1,595 Days
• Field of Search: 701117-119, 701200-202, 701213-215, 340/907, 340909-911, 340/933, 340/937, 340/943
• US Class Current: 701/119
• CPC Class Codes: G01S 13/91 for traffic control G01S13/93 takes precedence
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions
• CPC Class Codes: G08G 1/07 Controlling traffic signals

Abstract

The present invention extends to methods, systems, and computer program products for monitoring signalized traffic flow. A processor in a sensor system or traffic controller interface estimates the time-of-arrival and other traffic flow estimates of one or more vehicles to an intersection stop bar, while the vehicles are within a continuous range of one or more transducers view of the sensor system. A level of efficiency and safety within the signalized traffic flow is estimated by the sensor system based upon one or more of the estimated time-of-arrival and other flow variables estimates and then communicated to the control unit of the traffic signal system. Other flow estimates for each vehicle include but are not limited to: position relative to the stop bar, lane position, velocity, acceleration, time headway and classification.

Claims

1. At a roadway mounted sensor, the roadway mounted sensor monitoring vehicles on a portion of a roadway, a method for monitoring a signalized traffic flow, the method comprising:

an act of receiving sensor data, the sensor data indicating the presence of one or more vehicles within a continuous range of the monitored portion of the roadway, the received sensor data representing a portion of a signal that was transmitted by the roadway sensor into the portion of the roadway;

an act of using the received sensor data to determine estimated times-of-arrival of the one or more vehicles to a traffic control point associated with the monitored portion of the roadway, two or more times while the one or more vehicles are within the continuous range;

an act of determining a level of efficiency and safety for the traffic flow within the vicinity of the traffic control point based upon the estimated times-of-arrival; and

an act of reporting the level of efficiency and safety to a traffic control unit that is actively controlling the monitored signalized traffic flow.

2. The method as recited in claim 1, wherein the an act of using the received sensor data to determine estimated times-of-arrival of the one or more vehicles to a traffic control point associated with the monitored portion of the roadway comprises an act of determining estimated times-of-arrival to a traffic control point selected from among the following:

a stop bar, a crosswalk, a termination of an approach into an intersection, a location of a warning flasher, a location of a variable message sign, and a traffic control sign.

3. The method as recited in claim 1, wherein the continuous range comprises at least one of the following:

an extent of a dilemma zone, an extent of an early warning zone, and an extent of a clearing zone.

4. The method as recited in claim 1, wherein the continuous range comprises one or more lanes.

5. The method as recited in claim 4, wherein the act of determining the level of efficiency and safety comprises an act of estimating a per lane level of efficiency and safety.

6. The method as recited in claim 1, further comprising:

an act of comparing the estimated time-of-arrival to an upper arrival time bound; and

an act of comparing the estimated time-of-arrival to a lower arrival time bound.

7. The method as recited in claim 6, further comprising:

an act of setting the upper arrival time bound via a configuration utility; and

an act of setting the lower arrival time bound via a configuration utility.

8. The method as recited in claim 7, further comprising:

an act of setting the either the upper arrival time bound or the lower arrival time bound via a configuration utility;

an act of setting a desirable arrival time span via a user configuration utility; and

an act of determining the other arrival time bound using the desirable arrival time span and the set arrival time bound.

9. The method as recited in claim 8, wherein the act of setting a desirable arrival time span via a user configuration utility comprises at least one of the following:

an act of setting a desirable time headway between vehicles;

an act of setting a desirable rate of vehicle flow;

an act of setting a ratio indicating a desirable level of capacity usage as a ratio or percentage;

an act of setting a desirable time gap between vehicles.

10. The method as recited in claim 6, wherein the upper arrival time bound and the lower arrival time bound dynamically adapt.

11. The method as recited in claim 6, further comprising:

an act of determining the number of time-of-arrival estimates greater than the lower arrival time bound and less than the upper arrival time bound;

an act of signaling the traffic controller when the number of time-of-arrival estimates exceeds a count threshold.

12. The method as recited in claim 11, further comprising:

an act of setting the count threshold via a configuration utility.

13. The method as recited in claim 11, wherein the count threshold dynamically adapts.

14. The method as recited in claim 6, further comprising:

an act of comparing another traffic flow estimate detected within the continuous range to a bound.

15. The method as recited in claim 14, wherein the bound dynamically adapts.

16. The method as recited in claim 14, further comprising:

an act of setting the bound via a configuration utility.

17. The method as recited in claim 14, wherein the act of comparing another traffic flow estimate detected within the continuous range to a bound comprises an act of comparing another traffic flow estimate detected within the continuous range to a bound selected from among:

a lower velocity bound, an upper velocity bound, a lower distance bound, an upper distance bound, a lower acceleration bound, an upper acceleration bound, a lower classification bound, an upper classification bound;

a lower time headway bound, and an upper time headway bound.

18. The method as recited in claim 6, further comprising:

an act of setting a compensation factor that adjusts the estimated time-of-arrival by a percentage before comparison to the upper arrival time bound and the lower arrival time bound.

19. The method as recited in claim 1, wherein the act of determining estimated times-of-arrival of the one or more vehicles to a traffic control point associated with the monitored portion of the roadway, comprises:

an act of detecting an individual vehicle from within the received sensor data;

an act of estimating a position of the vehicle relative to the traffic control point;

an act of estimating a velocity of the vehicle; and

an act of estimating the time-of-arrival of the vehicle to the traffic control point based upon at least the estimated velocity and the estimated position.

20. The method as recited in claim 19, wherein the act of detecting an individual vehicle from within the received data comprises an act of discovering and tracking one or more vehicles within the continuous range.

21. The method as recited in claim 19, wherein the act of estimating the velocity comprises an act of monitoring the change in the estimated position of an identified vehicle over a period of time.

22. The method as recited in claim 19, wherein the act of estimating the time-of-arrival of the vehicle to the traffic control point comprise an act of mathematically dividing the estimated position by the estimated velocity.

23. The method as recited in claim 19, wherein the act of estimating the time-of-arrival of the vehicle to the traffic control point comprises an act of modeling the flow dynamics of the vehicles based upon at least the estimated speed and the estimated position.

24. The method as recited in claim 19, further comprising:

an act of determining an estimated vehicle acceleration by monitoring the change in the velocity over a period of time.

25. The method as recited in claim 19, further comprising:

an act of determining an estimated vehicle classification.

26. The method as recited in claim 25, wherein the act of determining an estimated vehicle classification comprises an act of determining one or more of an estimated vehicle length, an estimated vehicle height, and a level of received energy from a vehicle.

27. The method as recited in claim 26, wherein the act of determining an estimated vehicle length comprises an act of determining a duration of a vehicle within a transducer view.

28. The method as recited in claim 26, wherein the act of determining an estimated vehicle length comprises an act of determining an instantaneous extent of a vehicle within a continuum of transducer views.

29. The method as recited in claim 26, wherein the act of determining an estimated vehicle height comprises an act of orienting one or more transducer views to discriminate vertically.

30. The method as recited in claim 19, further comprising:

an act of estimating a time headway.

31. The method as recited in claim 1, wherein the act of reporting the level of efficiency and safety comprises an act of signaling the estimated level of efficiency and safety to a traffic control device.

32. The method as recited in claim 31, wherein the estimated level of efficiency and safety is signaled via one or more contact closures.

33. The method as recited in claim 31, wherein the level of efficiency and safety is within one or more bounds.

34. The method as recited in claim 33, further comprising:

an act of setting the one or more bounds via a configuration utility.

35. The method as recited in claim 33, wherein the one or more bounds dynamically adapt.

36. The method as recited in claim 1, wherein the continuous range comprises at least one or more of the following:

a continuous range as defined by a single detector and a continuous range as defined by multiple contiguous detectors grouped together for reporting the level of efficiency and safety.

37. The method as recited in claim 1, wherein the sensor is a radar.

38. The method as recited in claim 37, wherein the radar is an FMCW radar.

39. At a roadway mounted sensor, the roadway mounted sensor monitoring vehicles on a portion of a roadway, a method of monitoring traffic with the roadway mounted sensor, comprising:

an act of receiving sensor data, the sensor data indicating a presence of one or more vehicles within a continuous range of the monitored portion of the roadway, the received sensor data representing a portion of a signal that was transmitted by the roadway sensor into the portion of the roadway;

an act of using the received sensor data to determine estimated times-of-arrival of the one or more vehicles to a traffic control point associated with the monitored portion of the roadway in traffic flow while the one or more vehicles are within the continuous range;

an act of receiving further sensor data, the further sensor data indicating the presence of the one or more vehicles within the continuous range of the monitored portion of the roadway;

an act of using the received further sensor data to update estimated times-of-arrival of the one or more vehicles to the traffic control point while the one or more vehicles are within the continuous range subsequent to using the received sensor data to determine estimated times-of-arrival of the one or more vehicles; and

an act of reporting the updated estimated times-of-arrival.

40. The method as recited in claim 39, wherein the act of reporting comprises displaying the updated estimated times-of-arrival within one or more of the following:

a configuration utility, a traffic management system, a computer display, a sensor display, a display of computing device.

41. The method as recited in claim 39, wherein the act of reporting the updated estimated times-of-arrival comprises:

an act of displaying a representation of uniquely identified vehicles; and

an act of displaying the updated estimated times-of-arrival with the representation of uniquely identified vehicles.

42. The method as recited in claim 39, further comprising:

an act of adjusting a configuration parameter of the sensor.

43. The method as recited in claim 39, wherein the sensor is a radar.

44. The method as recited in claim 43, wherein the radar is an FMCW radar.

45. At a roadway mounted sensor, the roadway mounted sensor monitoring vehicles on a portion of a roadway, a method of monitoring traffic with the roadway mounted sensor, comprising:

an act of receiving sensor data, the sensor data indicating a presence of one or more vehicles within a continuous range of the monitored portion of the roadway, the received sensor data representing a portion of a signal that was transmitted by the roadway sensor into the portion of the roadway;

an act of dynamically adapting a location of detections for each of the one or more vehicles within the continuous range based upon a traffic characteristic, including;

an act of using the received sensor data a plurality of times to determine estimated times-of-arrival of the one or more vehicles to a traffic control point associated with the monitored portion of the roadway while the one or more vehicles are within the continuous range;

an act of reporting detections at the location of detections for each of the one or more vehicles as the location of detections dynamically adapt.

46. The method as recited in claim 45, further comprising:

an act of dynamically adapting a length of detection within the continuous range based upon the traffic characteristic.

47. The method as recited in claim 45, wherein the traffic characteristic is an estimated velocity of the vehicles.

48. The method as recited in claim 45, wherein the location of detection dynamically adapts on a lane-by-lane basis.

49. The method as recited in claim 45, wherein the length of detection dynamically adapts on a lane-by-lane basis.

50. The method as recited in claim 45, wherein the act of reporting detections at the location of detection comprises an act of reporting the detections to a traffic control device.

51. The method as recited in claim 45, wherein the sensor is a radar.

52. The method as recited in claim 51, wherein the radar is an FMCW radar.