Combining road and vehicle traffic information

• US 8,880,323 B2
• Filed: 08/15/2008
• Issued: 11/04/2014
• Est. Priority Date: 08/16/2007
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Jain, Ravi, Goel, Samir, Neverov, Gregory
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Malhotra, Sanjeev
• Application Number:
  US12/673,759
• Publication Number:
  US 20100286899A1
• Time in Patent Office: 2,272 Days
• Field of Search: 701/117, 701/200, 702/6, 706/11, 707/10, 714/40
• US Class Current: 701/119
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions
• CPC Class Codes: G08G 1/127 to a central station ; Indicators in a central station

Abstract

A computer-implemented method includes obtaining road sensor data reflecting speeds of traffic on road segments, transforming the road sensor data using vehicle probe data for the road segments reflecting vehicle speeds, and producing speed estimates for the road segments using the transformed road sensor data. The method can further include determining speeds for road segments between road sensors by smoothing data from sensors near the road segments.

Claims

1. A computer-implemented method, comprising:

obtaining a plurality of sensor data pairs from a stationary road sensor disposed at a first location along a road segment, each of the sensor data pairs comprising a traffic speed value that reflects speed, at the first location, of actual traffic on the road segment and a traffic speed time at which the corresponding traffic speed value was captured;

obtaining a plurality of probe data sets from one or more moving probes, each of the probe data sets comprising a probe speed value for a probe traveling along the road segment, a location indicator specifying a probe location along the road segment for which the probe speed value was determined, and a time indicator specifying a time for which the probe speed value was determined;

matching one or more sensor data pairs from the stationary road sensor to one or more probe data sets from the one or more moving probes;

performing, by a processor, regression analysis on the matched one or more sensor data pairs and one or more probe data sets to determine a transform to apply to the traffic speed values obtained from the road sensor, the regression analysis comprising comparison of data derived from the stationary road sensor and data derived from the one or more moving probes; and

applying the transform to at least one traffic speed value obtained from the stationary road sensor to provide an updated traffic speed value that differs from an initial traffic speed value obtained from the stationary road sensor, and providing the updated traffic speed value as a value that represents traffic speed in a vicinity of the stationary road sensor.

2. The method of claim 1, wherein the one or more probes comprise a communication or navigation system outfitted in a vehicle traveling along the road segment.

3. The method of claim 1, wherein the one or more probes comprise a probe vehicle.

4. The method of claim 1, wherein the one or more moving probes comprise a mobile device carried by a user in a vehicle traveling along the road segment.

5. The method of claim 1, wherein performing regression analysis comprises performing Bayesian linear regression analysis.

6. The method of claim 5, wherein performing Bayesian linear regression analysis comprises performing Bayesian linear regression analysis with a strong prior that favors a solution of vehicle speed value=traffic speed value+0.

7. The method of claim 1, wherein matching comprises identifying a probe data set whose location indicator specifies a probe location within a threshold distance of the first location and whose time indicator specifies a time that is within a threshold period of the traffic speed time.

8. The method of claim 7, further comprising forming a group of multiple matched sensor data pairs and probe data sets, wherein performing regression analysis comprises performing regression analysis on the group.

9. The method of claim 8, wherein forming the group comprises forming the group based on a time of day to which the traffic speed times in the sensor data pairs and the time indicators in the matched probe data sets correspond.

10. The method of claim 9, wherein the time of day is characterized by a period of time that is longer than the threshold period.

11. The method of claim 1, further comprising:

obtaining other pluralities of sensor data pairs from other stationary road sensors disposed at locations other than the first location along the road segment;

matching other probe data sets with other sensor data pairs received from the other pluralities; and

performing linear regression analysis on the matched other probe data sets and other sensor data pairs to determine other transforms to apply to traffic speed values obtained from each of the other stationary road sensors.

12. The method of claim 11, wherein the road sensor and other road sensors provide superior coverage of the road segment but inferior accuracy in traffic speed values, and the one or more probes provide superior accuracy in vehicle speed values but inferior coverage of the road segment.

13. The method of claim 11, wherein performing regression analysis comprises performing regression analysis at a first period of time;

and applying the transform comprises applying the transform at a second period of time that is subsequent to the first period of time and in substantially real time to obtaining the at least one traffic speed value from the road sensor.

14. The method of claim 13, further comprising receiving a request for a current traffic speed value at the first location and subsequently providing, in real time, the updated traffic speed value.

15. One or more devices having tangible, computer readable media storing instructions that, when executed by one or more computer processors, perform operations comprising:

obtaining a plurality of sensor data pairs from a stationary road sensor disposed at a first location along a road segment, each of the sensor data pairs comprising a traffic speed value that reflects speed, at the first location, of actual traffic on the road segment and a traffic speed time at which the corresponding traffic speed value was captured;

obtaining a plurality of probe data sets from one or more moving probes, each of the probe data sets comprising a probe speed value for a probe traveling along the road segment, a location indicator specifying a probe location along the road segment for which the probe speed value was determined, and a time indicator specifying a time for which the probe speed value was determined;

matching one or more sensor data pairs from the stationary road sensor to one or more probe data sets from the one or more moving probes;

performing regression analysis on the matched one or more sensor data pairs and one or more probe data sets to determine a transform to apply to the traffic speed values obtained from the road sensor, the regression analysis comprising comparison of data derived from the stationary road sensor and data derived from the one or more moving probes; and

applying the transform to at least one traffic speed value obtained from the stationary road sensor to provide an updated traffic speed value that differs from an initial traffic speed value obtained from the stationary road sensor, and providing the updated traffic speed value as a value that represents traffic speed in a vicinity of the stationary road sensor.

16. The one or more devices of claim 15, wherein the one or more probes comprise a communication or navigation system outfitted in a vehicle traveling along the road segment.

17. The one or more devices of claim 15, wherein the one or more moving probes comprise a mobile device carried by a user in a vehicle traveling along the road segment.

18. The one or more devices of claim 15, wherein performing regression analysis comprises performing Bayesian linear regression analysis with a strong prior that favors a solution of vehicle speed value=traffic speed value+0.

19. The one or more devices of claim 15, wherein performing regression analysis comprises performing regression analysis at a first period of time;

and

applying the transform comprises applying the transform at a second period of time that is subsequent to the first period of time and in substantially real time to obtaining the at least one traffic speed value from the road sensor.

20. The one or more devices of claim 15, further comprising receiving a request for a current traffic speed value at the first location and subsequently providing, in real time, the updated traffic speed value.