Determination of a free-flow speed for a link segment

• US 9,761,133 B2
• Filed: 06/26/2015
• Issued: 09/12/2017
• Est. Priority Date: 06/26/2015
• Status: Active Grant

• Current Assignee: HERE Global B.V. (Nokia Corporation)
• Original Assignee: HERE Global B.V. (Nokia Corporation)
• Inventors: Macfarlane, Jane
• Primary Examiner(s): SMITH, JELANI A
• Application Number:
  US14/751,682
• Publication Number:
  US 20160379489A1
• Time in Patent Office: 809 Days
• CPC Class Codes: G08G 1/0112 from the vehicle, e.g. floating car data [FCD]
• CPC Class Codes: G08G 1/0129 for creating historical data or processing based on historical data
• CPC Class Codes: G08G 1/0133 for classifying traffic situation
• CPC Class Codes: G08G 1/0141 for traffic information dissemination

Abstract

A method comprising determining speed-time cluster application histogram data set for a link segment that comprises a plurality of speed-time cluster application histogram data elements, each speed-time cluster application histogram data element identifying a speed-time cluster and an applicable duration of the speed-time cluster for the link segment throughout a histogram duration, for each speed-time cluster application histogram data element, determining a free-flow speed that is representative of a non-congestion speed indicated by the speed-time cluster, determining a historically normalized free-flow speed for the link segment that is a weighted average of the free-flow speed determined for each speed-time cluster application histogram data element weighted by the applicable duration of the speed-time cluster application histogram data element, and identifying a transit speed of the link segment as being the historically normalized free-flow speed is disclosed.

Claims

1. An apparatus, comprising:

at least one processor;

at least one memory including computer program code, the memory and the computer program code configured to, working with the processor, cause the apparatus to perform at least the following;

receiving probe data collected by one or more sensors;

determining, from the probe data, a speed-time cluster application histogram data set for a link segment that comprises a plurality of speed-time cluster application histogram data elements, each speed-time cluster application histogram data element identifying a speed-time cluster and an applicable duration of the speed-time cluster for the link segment throughout a histogram duration;

for each speed-time cluster application histogram data element, determining a free-flow speed that is representative of a non-congestion speed indicated by the speed-time cluster;

calculating, by a processor, a historically normalized free-flow speed for the link segment that is a weighted average of the free-flow speed determined for each speed-time cluster application histogram data element weighted by the applicable duration of the speed-time cluster application histogram data element;

calculating, by the processor, a predicted transit speed of the link segment as being the historically normalized free-flow speed; and

providing the predicted transit speed to a map or a navigation system.

2. The apparatus of claim 1, wherein a link segment is at least a portion of at least one of a route, a lane, a road, a highway, a street, a trail, or a thoroughfare.

3. The apparatus of claim 1, wherein the determining the speed-time cluster application histogram data set comprises:

receiving probe data indicative of speed of travel along the link segment;

identifying an applicable speed-time cluster associated with the link segment that is applicable to the probe data;

determining an applicable duration throughout the histogram duration in which the applicable speed-time cluster is applicable to the probe data; and

determining a speed-time cluster application histogram data element of the speed-time cluster application histogram data set that indicates the applicable speed-time cluster and the applicable duration.

4. The apparatus of claim 1, wherein the determining the free-flow speed comprises:

identifying of portions of the speed-time cluster that are indicative of non-congestion; and

determining the free-flow speed based on a speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

5. The apparatus of claim 4, wherein the determining the free-flow speed based on the speed indicated by the identified portions of the speed-time cluster omits portions of the speed-time cluster that are indicative of congestion.

6. The apparatus of claim 4, wherein the determining the free-flow speed based on the speed indicated by the identified portions of the speed-time cluster comprises determining the free-flow speed based on a maximum speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

7. The apparatus of claim 4, wherein the determining the free-flow speed based on the speed indicated by the identified portions of the speed-time cluster comprises determining the free-flow speed based on a percentage of a maximum speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

8. The apparatus of claim 7, wherein the percentage is between 80 percent and 90 percent.

9. The apparatus of claim 1, wherein the memory includes computer program code configured to, working with the processor, cause the apparatus to perform:

determining that the link segment is geospatially associated with a set of link segments; and

identifying a transit speed of the set of link segments as being the historically normalized free-flow speed.

10. A method comprising:

determining speed-time cluster application histogram data set for a link segment that comprises a plurality of speed-time cluster application histogram data elements, each speed-time cluster application histogram data element identifying a speed-time cluster and an applicable duration of the speed-time cluster for the link segment throughout a histogram duration;

for each speed-time cluster application histogram data element, determining a free-flow speed that is representative of a non-congestion speed indicated by the speed-time cluster;

determining a historically normalized free-flow speed for the link segment that is a weighted average of the free-flow speed determined for each speed-time cluster application histogram data element weighted by the applicable duration of the speed-time cluster application histogram data element;

calculating a predicted transit speed of the link segment as being the historically normalized free-flow speed; and

providing the predicted transit speed to a map or a navigation system.

11. The method of claim 10, wherein the determining the speed-time cluster application histogram data set comprises:

receiving probe data indicative of speed of travel along the link segment;

identifying an applicable speed-time cluster associated with the link segment that is applicable to the probe data;

determining an applicable duration throughout the histogram duration in which the applicable speed-time cluster is applicable to the probe data; and

determining a speed-time cluster application histogram data element of the speed-time cluster application histogram data set that indicates the applicable speed-time cluster and the applicable duration.

12. The method of claim 10, wherein the determining the free-flow speed comprises:

identifying portions of the speed-time cluster that are indicative of non-congestion;

and determining the free-flow speed based on a speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

13. The method of claim 12, wherein the determining the free-flow speed based on the speed indicated by the identified portions of the speed-time cluster omits portions of the speed-time cluster that are indicative of congestion.

14. The method of claim 12, wherein the determining the free-flow speed based on the speed indicated by the identified portions of the speed-time cluster comprises determining the free-flow speed based on a maximum speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

15. The method of claim 12, wherein the determining the free-flow speed based on the speed indicated by the identified portions of the speed-time cluster comprises determining the free-flow speed based on a percentage of a maximum speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

16. The method of claim 10, further comprising:

determining that the link segment is geospatially associated with a set of link segments; and

identifying a transit speed of the set of link segments as being the historically normalized free-flow speed.

17. At least one non-transitory computer-readable medium encoded with instructions that, when executed by a processor, perform:

determining a speed-time cluster application histogram data set for a link segment that comprises a plurality of speed-time cluster application histogram data elements, each speed-time cluster application histogram data element identifying a speed-time cluster and an applicable duration of the speed-time cluster for the link segment throughout a histogram duration;

for each speed-time cluster application histogram data element, determining a free-flow speed that is representative of a non-congestion speed indicated by the speed-time cluster;

determining a historically normalized free-flow speed for the link segment that is a weighted average of the free-flow speed determined for each speed-time cluster application histogram data element weighted by the applicable duration of the speed-time cluster application histogram data element;

calculating a predicted transit speed of the link segment as being the historically normalized free-flow speed; and

sending the predicted transit speed to a navigation system or a map system.

18. The medium of claim 17, wherein the determining the speed-time cluster application histogram data set comprises:

receiving of probe data indicative of speed of travel along the link segment;

identifying an applicable speed-time cluster associated with the link segment that is applicable to the probe data;

determining an applicable duration throughout the histogram duration in which the applicable speed-time cluster is applicable to the probe data; and

determining a speed-time cluster application histogram data element of the speed-time cluster application histogram data set that indicates the applicable speed-time cluster and the applicable duration.

19. The medium of claim 17, wherein the determining the free-flow speed comprises:

identifying portions of the speed-time cluster that are indicative of non-congestion; and

determining the free-flow speed based on a speed indicated by the identified portions of the speed-time cluster that are indicative of non-congestion.

20. The medium of claim 17, further encoded with instructions that, when executed by a processor, perform:

determining that the link segment is geospatially associated with a set of link segments; and

identifying a transit speed of the set of link segments as being the historically normalized free-flow speed.