Route calculation method for a vehicle navigation system

Abstract

Traffic information, including flow information and incident information, obtained through a traffic management system for providing and facilitating the exchange of traffic information between a remote location and a vehicle may be used in route calculation by a navigation device. The navigation device may recalculate a route based on anticipated user error. Alternatively, the navigation device may recalculate a route using received traffic information triggered by the receipt of a traffic information update, or triggered by the passage of an amount of time. The broadcast rate of traffic information updates may vary temporally (providing more frequent updates during peak commute times) or geographically (providing more frequent updates to metropolitan areas with increased traffic information needs). If route calculation is triggered by an elapsed amount of time, the amount of time may vary to be shorter during peak commute times. Additional route calculation techniques allow the incorporation of historical traffic information or the use of the most recent traffic information if incomplete traffic information is available. Still further route calculation techniques may calculate a best route by avoiding zigzagging or evaluating an assigned cost of a potential route.