Data mining in a digital map database to identify speed changes on upcoming curves along roads and enabling precautionary actions in a vehicle

• US 20090299624A1
• Filed: 05/30/2008
• Published: 12/03/2009
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: HERE Global B.V. (Nokia Corporation)
• Original Assignee: Navteq North America LLC (Nokia Corporation)
• Inventors: Denaro, Robert
• Granted Patent: US 10,648,817 B2
• Time in Patent Office: Days
• US Class Current: 701/208
• CPC Class Codes: B60W 40/02 related to ambient conditions
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 21/3697 Output of additional, non-guidance related information, e.g. low fuel level G01C21/3679 takes precedence
• CPC Class Codes: G09B 29/007 using computer methods

Abstract

Disclosed is a feature for a vehicle that enables taking precautionary actions in response to conditions on the road network around or ahead of the vehicle, in particular, a speed limit change that occurs between a straight road section and a curved road section. A database that represents the road network is used to determine locations where a speed limit change occurs between a straight road section and a curved road section along a road. Then, precautionary action data is added to the database to indicate a location at which a precautionary action is to be taken about the speed limit change between a straight road section and a curved road section. A precautionary action system installed in a vehicle uses this database, or a database derived therefrom, in combination with a positioning system to determine when the vehicle is at a location that corresponds to the location of a precautionary action. When the vehicle is at such a location, a precautionary action is taken by a vehicle system as the vehicle is approaching a speed limit change that occurs between a straight road section and a curved road section.

Claims

1. A method for making a database that represents a road network in a geographic region, the method comprising:

using data contained in the database to identify locations where a speed limit change occurs between a straight road section and a curved road section located along roads throughout the geographic region; and

adding precautionary action data to the database to indicate a condition for which a precautionary action is to be taken by a vehicle system.

2. The method of claim 1 further comprising:

selecting from the database data records that represents road segments;

upon determining that a road segment leads to a curved road segment and that a speed limit change occurs between the straight road segment and the curved road segment, adding the precautionary action data to the database to indicate the presence of a condition for which a precautionary action is to be taken.

3. The method of claim 2 further wherein the road segment is determined to have a speed limit change between a straight road section and a curved road section by evaluating shape point data associated with a successor road segment.

4. The method of claim 2 further comprising:

continuing to select from the database data records that represent road segments to identify all locations where a speed limit change occurs between a straight road section and a curved road section throughout the geographic region.

5. The method of claim 2 further comprising:

continuing to select from the database data records that represent road segments until all data records that represent road segments have been selected.

6. The method of claim 1 further comprising:

compiling the database into a format suitable for use in a navigation system.

7. The method of claim 1 wherein the step of using data contained in the database comprises evaluating at least two items of data contained in the database to determine whether a speed limit change occurs between a straight road section and a curved road section located along a road.

8. A database stored on a computer-readable medium, wherein the database includes data that represents a road network in a geographic region, wherein the database comprises:

data records that represent road segments that make up the road network;

data that indicate a speed limit change occurs between a straight road section and a curved road section along the road network; and

data that indicates precautionary action locations, wherein a precautionary action location is associated with a location where a speed limit change occurs between a straight road section and a curved road section along the road network.

9. The database of claim 8 wherein the precautionary action data further includes data that indicates a location along a road segment at which a precautionary action is to be taken by a vehicle system.

10. The database of claim 8 wherein the precautionary action data further includes data that indicates a direction along a road segment at which a precautionary action is to be taken.

11. The database of claim 8 wherein the precautionary action data further includes data that refers to the location of the actual speed limit change that occurs between a straight road section and a curved road section.

12. The database of claim 8 further comprising data that indicates permitted directions of travel along road segments, speed limits along road segments, classifications of road segments, and locations of road segments.

13. The database of claim 8 further comprising data that identifies successor road segments of each road segment, wherein successor road segments are those road segments that connect to a road segment at each end thereof.

14. A vehicle system comprising:

a database that contains data representing a geographic region in which a vehicle is being operated, wherein the data includes data that represents a road network located in the geographic region and precautionary action data that indicates precautionary action locations associated with locations where a speed limit change occurs between a straight road section and a curved road section along roads;

a positioning system that determines a current location of the vehicle relative to the data representing a geographic region; and

a precautionary action application responsive to the positioning system and the database that provides a precautionary action when the positioning system determines that the current location of the vehicle is approaching a speed limit change between a straight road section and a curved road section located along a road.

15. The system of claim 14 wherein the precautionary action data further includes data that indicates a location along a road segment at which a precautionary action is to be taken by a vehicle system.

16. The system of claim 14 wherein the precautionary action data further includes data that indicates a direction along a road segment at which a precautionary action is to be taken.

17. The system of claim 14 wherein the precautionary action data further includes data that refers to the location of the actual speed limit change between a straight road section and a curved road section along the road.

18. A method for providing precautionary actions in a vehicle comprising:

determining a current position of the vehicle;

accessing a database that represents a road network to obtain data representations of a part of the road network around of the current position of the vehicle; and

upon determining that the data representations of the part of the road network around the current position of the vehicle include precautionary action data, taking a precautionary action as the vehicle is approaching a speed limit change that occurs between a straight road section and a curved road section along a road.

19. The method of claim 18 further comprising:

building an electronic horizon after accessing the database; and

using the electronic horizon to determine whether precautionary action data is included therein.

20. The method of claim 18 wherein the precautionary action is provided via a user interface of the vehicle.