Navigation system and method for calculating a guide route

A navigation system comprising:

• position detection means for detecting a present position of a vehicle;
• destination input means for identifying a destination;
• map data storage means for storing road data for a plurality of roads, including a statistical required time for at least some of the roads where the statistical required time associated with a particular road represents the time required for actually traveling the road, statistically obtained, and is not based on traffic information transmitted to the vehicle from outside the vehicle, and by-pass road information to indicate whether or not a road is a by-pass road;
• route search processing means for searching a guide route from a present position detected by the position detection means to a destination identified by the destination input means on the basis of the road data;
• route guiding means for guiding a driver to the destination in accordance with the guide route searched by the route search processing means;
• and
• required time calculation means for calculating an estimated arrival time at the destination or a required time to reach the destination, wherein the required time calculation means calculates an estimated arrival time at the destination or a required time to reach the destination by using a time to pass through a road, obtained on the basis of received traffic information when traffic information transmitted from outside the vehicle is received, and the statistical required time, when the traffic information is not available on a road and the statistical required time is available;
• wherein the statistical required time data is pre-set in the map data storage means and is determined without the involvement of a user, and as to a road identified as a by-pass road where the statistical required time and the traffic information is not available, the required time calculation means calculates a required time to pass through a unit distance that is shorter than a required time to pass through the unit distance on a non-by-pass road.

A method for searching a route, comprising the steps of:

• identifying a start point and a destination;
• reading out road data from a map data storage means containing road data for a plurality of roads, including a statistical required time for at least some of the roads where the statistical required time associated with a particular road represents the time required for actually traveling the road, statistically obtained, and is not based on traffic information transmitted to the vehicle from outside the vehicle, and by-pass road information to indicate whether or not a road is a by-pass road;
• and
• searching a route between the start point and the destination on the basis of the road data, wherein the route is searched by using a time to pass through a road obtained on the basis of received traffic information when traffic information transmitted from outside the vehicle is received, and the statistical required time when the traffic information is not available on a road and the statistical required time is available;
• wherein the statistical required time data is pre-set in the map data storage means and is determined without the involvement of a users and as to a road where the statistical required time and the traffic information is not available, a road identified as a by-pass road on the basis of the by-pass road information is given priority in searching a guide route.

A method for searching a route comprising the steps of:

• identifying a start point and a destination;
• reading out road data from a map data storage means containing road data for a plurality of roads, including a statistical required time for at least some of the roads where the statistical required time associated with a particular road represents the time required for actually traveling the road, statistically obtained, and is not based on traffic information transmitted to the vehicle from outside the vehicle, and by-pass road information to indicate whether or not a road is a by-pass road;
• searching a guide route from the start point to the destination on the basis of the road data;
• and
• calculating an estimated arrival time at the destination or a required time to reach the destination when guiding the driver to the destination in accordance with the searched guide route, wherein an estimated arrival time at the destination or a required time to reach the destination is calculated by using a time to pass through a road obtained on the basis of received traffic information when traffic information transmitted from outside a vehicle is received, and the statistical required time when the traffic information is not available on a road and the statistical required time is available;
• wherein the statistical required time data is pre-set in the map data storage means and is determined without the involvement of a user, and as to a road identified as a by-pass road where the statistical required time and the traffic information is not available, a required time to pass through a unit distance is set shorter than a required time to pass through the unit distance on a non-by-pass road.