Data mining in a digital map database to identify speed changes on upcoming curves along roads and enabling precautionary actions in a vehicle
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 such a location. 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 such a location, at which a precautionary action is taken by a vehicle system.
1. A method for making, prior to a vehicle's approach to a potentially hazardous location, a component configured for a vehicle system that provides a precautionary action in a vehicle when the vehicle approaches the potentially hazardous location, wherein the component comprises an augmented version of a database that represents a road network in a geographic region, and using the component to provide a precautionary action, the method comprising:
with a computer configured to operate under programming instructions, evaluating data contained in a first version of the database to identify locations along roads throughout the geographic region where a combination of a first condition and a second condition exist together at a same location wherein the first condition comprises a straight road section characterized in the database by no curvature followed by a curved road section characterized in the database by at least some curvature and wherein the second condition comprises a speed limit change between the straight road section and the curved road section;
with the computer configured to operate under programming instructions, upon determining existence of the second condition at the location of the first condition, adding precautionary action data in association with the location to form the augmented version of the database, such that the vehicle system of the vehicle, based upon the vehicle's approach to a location, may determine whether precautionary action data exists in the augmented version of the database in association with the approached location and, based on the existence thereof, take a precautionary action and wherein the vehicle system does not take a precautionary action based on the precautionary action data when precautionary action data does not exist in the augmented version of the database in association with the approached location;
coupling the augmented version of the database with the vehicle system of the vehicle, the vehicle system comprising a positioning system;
accessing the augmented version of the database based on a location obtained from the positioning system of the vehicle system;
determining whether precautionary action data exists in the augmented version of the database in association with the obtained location; and
providing the result of the determination to the vehicle system.
2. The method of claim 1 further comprising:
selecting from the first version of 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 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 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 first version of 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 first version of 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 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 evaluating 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 a speed limit change occurs between a straight road section and a curved road section located along a road.
8. The method of claim 1 wherein each straight road section is stored in the database in association with no shape points and each curved road section is stored in the database in association with at least one shape point.