Patent ID: 7031983

Claim:
A method of forming a geographic database stored on a computer-readable medium wherein the geographic database includes data that represent individual segments of roads and that can be used in a navigation system that also uses traffic messages broadcast by a traffic broadcast system that identify locations along roadways with location reference numbers wherein each of said traffic messages includes a location reference number that indicates a starting location of a reported traffic condition, wherein said location reference number identifies a designated location selected from an ordered sequence of designated locations along a road to which location reference numbers have been assigned, and data that indicates a physical distance that the reported traffic condition extends as an extent of the reported traffic condition, wherein said extent is expressed as a number of adjacent locations in said ordered sequence of designated locations extending from the starting location, the method comprising the steps of: storing in the geographic database on the computer-readable medium data that represent each individual road segment located in a region; and storing in the geographic database data that represent each location reference number, wherein the data that represent each location reference number identify the road segment upon which the designated location identified by said location reference number is located, the road segments leading to the road segment upon which the designated location identified by the location reference number is located, the immediately previous location reference number in said ordered sequence, and the immediately next location reference number in said ordered sequence, whereby the navigation system accesses the data in the geographic database stored on the computer-readable medium to relate the data contained in the traffic messages to road segments represented in the geographic database in order to use said traffic messages in said navigation system.