System and method for calculating an optimized route and calculation thereof

A route calculation program for use in a navigation system, the route calculation program adapted to calculate an optimal route from a first location to a second location along a road network located in a geographic region using a geographic database that represents the road network, wherein the optimal route has a characteristic optimized for a specific criterion, the route calculation program comprising the steps of:

• determining a bounding route between the first location and the second location by selecting segments of roads that have characteristics that best satisfy the specific criterion;
• determining a boundary value by assessing the characteristics of each selected segment of road of the bounding route;
• and
• selecting as the optimal route among all possible routes that has an optimal value for the characteristics of all subsequent route calculations that have a value for the characteristic that is less than the boundary value.

A method for calculating an optimal route from a first location to a second location along a road network located in a geographic region using a geographic database that represents the road network, wherein the optimal route has a characteristic optimized for a specific criterion, the method comprising the steps of:

• with a relatively fast algorithm optimized for the specific criterion, determining a boundary route from the first location to the second location using the geographic database,
• determining a boundary value for the characteristic, wherein the boundary value is that value by which the characteristic of the boundary route meets the specific criterion;
• and
• performing an exhaustive search of all possible routes between the first location and the second location that have a value for the characteristic that is less than the boundary value, selecting one of the all possible routes as the optimal route that has an optimal value for the characteristic.