System and method for estimating impedance time through a road network

A method for calculating a navigation route between first and second geographic locations through a roadway network of roads intersecting at nodes, comprising:

• providing a data structure having data indicative of a roadway network of roads intersecting at intersection nodes, said data including feature data indicative of traffic characteristics for associated roads;
• calculating a route impedance for a navigation route through said roadway network between first and second geographic locations based on said feature data;
• determining node impedances for intersection nodes though which the navigation route travels based on said feature data, said intersection nodes representing locations along the navigation route at which roads followed by the navigation route intersect other roads;
• and
• utilizing said node impedance and route impedance to calculate the navigation route.

A navigation system comprising:

• a storage unit holding a data structure having data indicative of roads in a roadway network and intersections of said roads at nodes;
• a route calculation module calculating a planned route over the roadway network between source and destination locations based on the data structure held in the storage unit;
• and
• a correction module for identifying undesirable shortcuts constituting predefined paths along said roads and through said nodes in said roadway network route that, while reducing an overall distance traveled by a planned route, are to be avoided in said planned route between said source and destination locations, said route calculation module avoiding said undesirable shortcuts.