Data mining for traffic signals or signs along road curves and enabling precautionary actions in a vehicle

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

using data contained in the database to identify locations along roads throughout the geographic region at which at least two conditions exist, wherein the two conditions include:

(i) presence of a stop sign or traffic light, and

(ii) curvature of the road; and

adding precautionary action data to the database to indicate a condition at said locations for which said at least two conditions exist 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 a data record that represents a road segment;

upon determining that the road segment includes a curved section, obtaining data that represent stop signs or traffic lights along the road segment; and

upon determining that the road segment includes a curved section and that a stop sign or traffic light is located along the curved section, 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 be curved by evaluating shape point data associated with the 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 of traffic lights or stop signs located along curved sections of roads 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 traffic light or stop sign is located along a curved section of road.

8. A database stored on a computer-readable medium, wherein the database includes non-transitory 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 indicates curvature of the road segments; and

precautionary action data that indicates precautionary action locations throughout the road network in the geographic region, wherein each precautionary action location is associated with a location along the road network where at which at least two conditions exist at a same location, wherein the two conditions include (i) presence of a traffic light or stop sign and (ii) a curved section of a road.

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 stop sign or traffic light located along the curved section of road.

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 throughout the road network in thegeographic region where at least two conditions exist at a same location, wherein the two conditions include (i) presence of a stop light or traffic light and (ii) presence of a curved section of road;

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 traffic light or stop sign located along a curved section of 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 stop sign or traffic light located along the curved section of 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 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, wherein precautionary action data indicates locations along the road network at which at least two conditions exist a same location, wherein the two conditions include (i) presence of a traffic light or stop sign and (ii) presence of a curved section of 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.