| 摘要 |
PROBLEM TO BE SOLVED: To provide a navigation system, a navigation method, and a navigation program which are capable of securing user safety and comfort by alleviating, when a vehicle enters a tunnel whose entrance and exit regions cannot be visually confirmed, the uneasiness felt by a user of the vehicle.SOLUTION: An onboard navigation device 1 comprises: a current location acquisition unit 2 for acquiring the current location of a vehicle; a tunnel information acquisition unit 5a for acquiring tunnel information; a tunnel specification unit 5c for specifying a tunnel which the vehicle enters; a determination unit 5d for determining whether or not an exit region of the specified tunnel can be visually confirmed from an entrance region of the tunnel via the interior of the tunnel, and, if determined not to be visually confirmable, determines that the specified tunnel is a tunnel to be guided; and a guidance unit 5e for providing, when determined that the specified tunnel is a tunnel to be guided, the user with guidance pertaining to the tunnel to be guided. |
