Data mining in a digital map database to identify insufficient merge lanes along roads and enabling precautionary actions in a vehicle

1. A method for making an augmented version of a database that is operable as a component in a vehicle system that provides a precautionary action in a vehicle when the vehicle approaches a potentially hazardous location, wherein the potentially hazardous location comprises one at which two conditions are present at a same location along a road network in a geographic region wherein one of the two conditions comprises absence of a traffic signal and another of the two conditions comprises a merge lane of insufficient dimensions, the method comprising:

with a computer operating under programming instructions, selecting data contained in a first version of a database to identify locations of intersections located throughout the geographic region where roads meet without a traffic signal and without a sufficient merge lane; and

forming, prior to the vehicle's approach to the potentially hazardous location, the augmented version of the database by adding precautionary action data to the database to indicate said potentially hazardous locations at which a precautionary action is to be taken by the vehicle system such that a determination can be made by the vehicle system whether to take a precautionary action based on an evaluation of the precautionary data in the augmented version of the database at a later time when the vehicle is at or near the potentially hazardous location.

2. The method of claim 1 further comprising:

selecting from the first version of the database a data records that represent an intersection of roads;

upon determining that no traffic signal is located at the intersection, obtaining data from the first version of the database that indicate whether a merge lane exists along the roads; and

upon determining that the intersection does not have a traffic signal and does not have a merge lane, adding the precautionary action data to the first version of 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 intersection is determined not to have a merge lane by evaluating data that indicates what geographic feature is adjacent to the roads leading to the intersection.

4. The method of claim 2 further comprising:

continuing to select from the first version of the database data that represent intersections to identify all locations of intersections that do not have a traffic signal and do not have a merge lane.

5. The method of claim 2 further comprising:

continuing to select from the first version of the database data that represent intersections until all data records that represent intersections have been selected.

6. The method of claim 1 further comprising:

compiling the augmented version of 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 first version of the database comprises evaluating at least two items of data contained in the first version of the database to determine whether an intersection lacks a sufficient merge lane.

8. A database stored on a non-transitory computer-readable medium, wherein the database includes data that represents a road network in a geographic region and wherein the database is operable as a component in a vehicle system that provides warnings when approaching potentially hazardous locations, wherein the database comprises:

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

data that indicates merge lanes along the road segments; and

data that indicates precautionary action locations, wherein a precautionary action location is associated with a location at which two conditions are present at a same location, wherein one of the two conditions comprises no merge lane or an insufficient merge lane and another of the two conditions comprises an intersection of roads without a traffic signal, such that the vehicle system need only perform a single evaluation to determine whether the precautionary data exists in the database to determine whether a precautionary action is to be taken upon approach to the potentially hazardous location.

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 intersection with the insufficient merge lane.

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 speed limits road segments.

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 insufficient merge lanes exist at intersections of roads without traffic signals such that the vehicle system need only perform a single evaluation to determine whether the precautionary data exists in the database to determine whether a precautionary action is to be taken upon approach to the potentially hazardous location;

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

a precautionary action application executed on a processor and responsive to the positioning system and the database wherein the precautionary action application determines whether the precautionary data exists in the database in associate with the current location of the vehicle and, based thereon, provides a precautionary action when the positioning system determines that the precautionary data exists in the database indicative that the current location of the vehicle is approaching an intersection without a traffic signal and with an insufficient merge lane.

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 location of the intersection with the insufficient merge lane.

18. A method performed with a program executed on a processor in a vehicle system for providing precautionary actions in a vehicle comprising:

accessing a database that includes data representations of a road network;

determining a current position of the vehicle relative to the road network represented by the database; and

upon determining that data representations of a part of the road network around the current position of the vehicle includes precautionary action data, the precautionary action data being indicative of an upcoming intersection without traffic signals and without a sufficient merge lane, taking a precautionary action, based on the inclusion of precautionary action data in the data representation of the part of the road network around the current position of the vehicle as the vehicle is approaching the intersection.

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.