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.