Patent ID: 7885764

Claim:
A method for constructing and revising road maps in a database for a vehicle, said method comprising: identifying vehicle travel segments of the vehicle as a series of exemplar points using signals from a system that provides vehicle position; eliminating intermediate exemplar points in each travel segment to define the travel segment by a beginning exemplar point and an ending exemplar point of the travel segment; storing the travel segments in the database; identifying a travel time associated with each stored travel segment; comparing new vehicle travel segments to the stored vehicle travel segments to identify matches between the new travel segments and the stored travel segments, and wherein comparing new vehicle travel segments to the stored vehicle travel segments includes projecting points on the new travel segment to the stored travel segment using a line perpendicular to the stored travel segment; replacing a potential ending exemplar point of a travel segment with a new ending exemplar point if the potential ending point causes an average distance between the exemplar points identifying the travel segment and a straight line between the beginning exemplar point and the potential ending exemplar point to be greater than a threshold distance; and revising the travel time of a stored travel segment if a new travel segment does match a stored travel segment.