Patent ID: 7353111

Claim:
A navigation system performing route guidance for a vehicle in which the navigation system is mounted, comprising: a preprocessing unit calculating a second-order differential value of speed of the vehicle as a jerk and calculating an value obtained by accumulating any one of an absolute value and a square value of the jerk in a certain period of time; a driving characteristic calculation unit determining whether the accumulated value is equal to or above a predetermined threshold value; a position/traveling direction determination unit determining a position and a traveling direction of the vehicle; a troublesome driving place database storing information of an intersection at which the accumulated value is calculated to be equal to or above the predetermined threshold value and information of the traveling direction of the vehicle at the intersection in association with each other; a troublesome driving place determination unit calculating a risk cost of a driver at each of intersections around the vehicle for each traveling direction of the vehicle with reference to the troublesome driving place database; and a route guidance unit configured to perform route guidance using the risk cost of a driver calculated by the troublesome driving place determination unit.