On-vehicle navigation apparatus, turnoff road guiding method, driving lane specifying device, and driving lane specifying method

1. An on-vehicle navigation apparatus comprising:

a current location calculator calculating a current location of an own vehicle;

a map information database storing map information including road map data;

a driving lane specifying section detecting a lane change in response to an operation signal from a winker and specifying a driving lane on which the own vehicle is traveling; and

a guidance timing controller detecting a turnoff road ahead of the own vehicle in a traveling direction based on the current location of the own vehicle and the road map data, and conducting a turnoff road guidance at a forward position which is between the detected turnoff road and the own vehicle; and

a guidance table determining the forward position for a location of the specified driving lane of the own vehicle, based on a combination of a jam-up status at the turnoff road, and a speed of the own vehicle.

2. The on-vehicle navigation apparatus according to claim 1 , further comprising:

a highway approach detector detecting an approach of the own vehicle toward a highway based on the current location of the own vehicle and the road map data, and sending a signal to the driving lane specifying section indicating that the own vehicle is approaching toward the highway.

3. The on-vehicle navigation apparatus according to claim 1 , wherein:

the driving lane specifying section includes a white line detector detecting a white line in a forward area of a road; and

the white line detector detects the operation signal from the winker and subsequently discriminates the lane change in response to a crossing signal indicative of whether the own vehicle straddles a white line rightward or leftward for thereby specifying the location of the driving lane on which the own vehicle is currently traveling.

4. The on-vehicle navigation apparatus according to claim 1 , further comprising:

a radio communication unit receiving traffic information including the jam-up status at the turnoff road.

5. The on-vehicle navigation apparatus according to claim 1 , wherein:

the turnoff road guidance provides a message with a content that is different depending on the position of the specified driving lane of the own vehicle.

6. The on-vehicle navigation apparatus according to claim 1 , wherein:

in cases where after the turnoff road guidance has been conducted at the forward position, the operation signal from the winker is not detected, the turnoff road guidance is repeatedly conducted.

7. A turnoff road guiding method comprising:

calculating a current location of an own vehicle;

detecting a lane change in response to an operation signal from a winker and specifying a driving lane on which the own vehicle is traveling;

detecting a turnoff road ahead of the own vehicle in a traveling direction based on the current location of the own vehicle and a road map data;

determining a forward position, which is between the detected turnoff road and the own vehicle, for a location of the specified driving lane of the own vehicle, based on a combination of a jam-up status at the turnoff road, and a speed of the own vehicle; and

conducting a turnoff road guidance on a driver at the forward position.

8. The turnoff road guiding method according to the claim 7 , further comprising:

discriminating a lane change in response to a crossing signal indicative of whether an own vehicle straddles a white line rightward or leftward.

9. An on-vehicle navigation apparatus comprising:

a current location calculation means calculating a current location of an own vehicle;

a map information storage means storing map information including road map data;

a driving lane specifying means detecting a lane change in response to an operation signal from a winker and specifying a driving lane on which the own vehicle is traveling; and

guidance timing control means detecting a turnoff road ahead of the own vehicle in a traveling direction based on the current location of the own vehicle and the road map data, and conducting a turnoff road guidance at a forward position which is between the detected turnoff road and the own vehicle; and

a guidance table determining the forward position for a location of the specified driving lane of the own vehicle, based on a jam-up status at the turnoff road, and a speed of the own vehicle.